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Obsession by Jennifer L. Armentrout, book cover

Obsession Summary

by Jennifer L. Armentrout

4.32 Goodreads · 15k ratingsMystery249 pages11-min summary

A deadly assassin must choose between his duty to protect a woman who saw his alien kind and a forbidden desire that could destroy them both.

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By BookBrief EditorialPublished March 2026How we write summaries

Synopsis

Covers the whole plot, including the ending.

Hunter, a lethal alien assassin working for the Department of Defense, is tasked with protecting Serena Cross, a human who witnessed her best friend's murder by an alien. While Hunter's usual assignments involve eliminating threats, this time he must shield Serena from his own kind, the Arum, and the powerful government forces intent on silencing her to maintain secrecy. Despite their initial clashes and profound differences, a powerful attraction sparks between Hunter and Serena. As Hunter finds himself breaking every rule and defying his handlers to ensure Serena's survival, they uncover a deeper conspiracy. The true danger to Serena's life becomes ambiguous: is it the predatory aliens, the clandestine government, or the very alien protector who is falling for her?
Difficulty
Easy
Pacing
Fast
Mood
Exciting, intense, romantic, suspenseful

Obsession Plot Summary

Covers the whole plot, including the ending.

  1. A Shocking Revelation

    Serena Cross's life changes when she sees her best friend, Melissa, brutally murdered. Melissa had been trying to convince Serena that she saw Senator Davis's son, Marcus, turn into something inhuman. Serena, skeptical at first, faces the truth when she sees Marcus, or the alien he becomes, kill Melissa. This event shatters Serena's reality and introduces her to a world where extraterrestrial beings, Luxen and Arum, exist, and their secrets are protected. Serena flees, now a target.

  2. Hunter's Unwelcome Assignment

    Hunter, a strong Arum, kills for the Department of Defense (DOD), eliminating Luxen and other threats. He has never questioned his purpose. However, he is assigned to protect a human, Serena Cross, from his own kind. This goes against his rules and instincts. He sees humans as weak, and guarding one, especially one who witnessed an Arum killing, angers him. Despite his dislike, he must follow orders, and his path is now tied to Serena's.

  3. Forced Proximity and Growing Tension

    Hunter takes Serena to a safe house, where their closeness immediately causes conflict. Serena is scared, confused, and angry; Hunter is cold, dismissive, and arrogant. Their personalities clash, leading to arguments and tension. Yet, an attraction begins to form. Serena is drawn to Hunter's dangerous power, despite her fear. Hunter is intrigued by Serena's spirit and resilience, qualities he did not expect in a human. This forbidden pull complicates their dangerous situation.

  4. The Threat Intensifies

    The Arum, led by Marcus, relentlessly pursue Serena. She is a loose end, having seen Melissa's murder, and the Arum will stop at nothing to silence her. Hunter constantly fights off attacks from his own kind, battling to protect Serena. These fights are physically and emotionally draining. Hunter struggles with protecting a human against his instincts and loyalty to his species. Each attack helps Serena understand the alien world and the constant danger she faces.

  5. Unraveling the Conspiracy

    As Hunter and Serena spend more time together, they uncover truths about the alien presence on Earth and the government's role. They realize the DOD, Hunter's employer, has its own agenda regarding the Luxen and Arum. The lines between good and bad blur, and Serena questions whom she can trust. Hunter also begins to question his loyalty to the DOD, realizing they might be using him. This reveals betrayal and danger from multiple sides.

  6. A Developing Connection

    Despite the danger and their initial dislike, Serena and Hunter's relationship deepens. Hunter, who first saw Serena as a burden, now genuinely cares for her safety. He starts to lower his guard, showing glimpses of the man beneath the killer. Serena sees past Hunter's coldness, recognizing his protectiveness and internal struggle. Their physical attraction grows, leading to passionate moments that strengthen their bond. This unexpected connection becomes a source of strength and vulnerability for them in a world trying to separate them.

  7. Breaking the Rules

    Hunter's growing feelings for Serena lead him to make choices he never thought possible. He starts to defy direct orders from the DOD, putting Serena's safety above his missions and his superiors. This puts him against both the government and his Arum brethren. He understands the severe consequences of his actions, knowing he could become a target. His willingness to sacrifice everything for Serena shows a deep change in his character and his devotion.

  8. The Final Confrontation

    The pursuit ends in a desperate and violent fight with Marcus and other Arum. Hunter and Serena are cornered, forced to fight for their lives against many enemies. Hunter uses his full Arum power, battling to protect Serena. Serena, no longer a passive victim, fights back, showing courage and resilience. The battle is brutal and high-stakes; they know failure means their deaths and the exposure of the alien secret, possibly leading to a larger conflict. This tests their bond and Hunter's commitment.

  9. Aftermath and Escape

    Against the odds, Hunter and Serena win the battle, though with significant injuries and emotional scars. Their ordeal is not over. By defying the DOD and killing several Arum, Hunter is now wanted by both sides. They are fugitives, with no clear path. They must live off the grid, constantly looking over their shoulders, knowing the government and the remaining Arum will hunt them. Their survival depends on trusting each other completely and relying on their wits and combined strength.

  10. A New Beginning

    After their experiences, Serena and Hunter build a new life together, in the shadows and constantly moving. Their bond, tested by fire, is an unbreakable love. Hunter, once a detached killer, has found a purpose beyond his missions in protecting and loving Serena. Serena, once an ordinary human, has adapted to a world of aliens and danger, finding strength and love in an unexpected place. Their future is uncertain and dangerous, but they face it together, their devotion to each other their greatest strength.

Obsession Characters

Hunter

Protagonist

A powerful, ruthless Arum assassin assigned to protect a human.

Hunter is a formidable and deadly Arum, a member of an alien race known for their ability to absorb energy and their predatory nature. He works for the Department of Defense, acting as a ruthless assassin against the Luxen and other threats. Initially, he is cold, arrogant, and dismissive of humans, viewing them as fragile and insignificant. His life is defined by his missions and his unwavering loyalty to his species and his handlers. He possesses immense power, a sharp intellect, and a detached demeanor that masks a capacity for deep emotion.

Relationships: Serena Cross (Love interest, protected human); Department of Defense (Employer, eventually defied); Marcus (Rival Arum, enemy)

Serena Cross

Protagonist

An ordinary human thrust into a dangerous world of aliens, becoming a target.

Serena is an ordinary young woman whose life is irrevocably changed after witnessing her best friend's murder by an alien. Initially skeptical and then terrified, she quickly demonstrates remarkable resilience, courage, and a fiery spirit. Despite being thrust into a world she never knew existed, she refuses to be a passive victim. She is intelligent, compassionate, and fiercely independent, often clashing with Hunter's domineering nature. Her humanity becomes a source of both vulnerability and unexpected strength.

Relationships: Hunter (Love interest, protector); Melissa (Best friend (deceased)); Marcus (Enemy, murderer of her friend)

Marcus

Antagonist

A powerful and ruthless Arum, the primary threat to Serena.

Marcus is a high-ranking and exceptionally dangerous Arum, the son of a powerful senator who secretly operates within human society. He is the one responsible for Melissa's murder and becomes the relentless hunter of Serena. Marcus embodies the predatory nature of the Arum, lacking empathy for humans and viewing them as disposable. He is cunning, sadistic, and possesses significant power, making him a formidable foe for both Serena and Hunter. He is driven by a desire to maintain the Arum's secrecy and eliminate any threats.

Relationships: Serena Cross (Target, enemy); Hunter (Rival Arum, enemy); Melissa (Victim)

Melissa

Supporting

Serena's best friend whose murder triggers the plot.

Melissa is Serena's best friend, whose initial claims of seeing an alien transformation are met with disbelief. She is the catalyst for the entire story, as her brutal murder by Marcus is what thrusts Serena into the world of Luxen and Arum. Though she appears only briefly and dies early in the narrative, her death serves as a constant reminder of the danger Serena faces and fuels Serena's determination to survive and understand what happened.

Relationships: Serena Cross (Best friend); Marcus (Murderer)

General Roth

Supporting

Hunter's handler at the Department of Defense.

General Roth is Hunter's superior within the Department of Defense, responsible for assigning his missions and overseeing Arum operations. He represents the government's vested interest in controlling the alien presence on Earth and maintaining secrecy. He is pragmatic, authoritative, and initially seems to have Hunter's best interests at heart, albeit within the confines of his duty. However, as Hunter's loyalty shifts, Roth becomes a figure of authority that Hunter must defy, revealing the DOD's potentially darker agenda.

Relationships: Hunter (Commander); Department of Defense (Leader)

Other Arum

Supporting

Hunter's brethren, mostly loyal to Marcus or the DOD.

These are various other members of the Arum species who appear throughout the novel. Some are loyal to Marcus and actively hunt Serena, serving as direct combatants against Hunter. Others might be working for the DOD, similar to Hunter, but their loyalty remains with their species or the government's objectives, making them potential threats if Hunter deviates too far from his orders. They embody the collective power and danger of the Arum race.

Relationships: Hunter (Species brethren, sometimes adversaries); Marcus (Allies or subordinates)

DOD Agents

Supporting

Human agents working for the Department of Defense.

These are the human operatives working under General Roth and the Department of Defense. They are aware of the alien presence and are tasked with managing or controlling it, as well as maintaining secrecy. While not possessing alien abilities, they are trained and equipped to handle extraordinary situations. They represent the human governmental power structure and their efforts to maintain order, even if it means questionable ethics. They become a threat to Hunter and Serena once Hunter goes rogue.

Relationships: Hunter (Colleagues (initially), pursuers (later)); General Roth (Superiors)

Obsession Themes

Forbidden Love

The main theme is the intense and dangerous romance between Hunter, an alien Arum, and Serena, a human. Their love is forbidden by societal norms, species differences, and the governmental and alien groups that want to control or kill them. Their relationship challenges Hunter's beliefs about humans and forces him to break his rules, showing love's power to cross boundaries.

“He was everything I shouldn't want, everything that was wrong, and yet... I wanted him more than I wanted my next breath.”
Serena's internal monologue

Identity and Belonging

Both Hunter and Serena deal with their identities. Hunter, an Arum, saw himself as a DOD tool, a killer without human emotions. His time with Serena forces him to question this and accept a more compassionate self. Serena, an ordinary human, is thrown into a world where her understanding of reality is shattered, making her redefine who she is and where she belongs in a universe with aliens. They both find a new sense of belonging with each other.

“I was a weapon, a killer, and I was good at it. But with her, I felt... something else. Something I hadn't known I was missing.”
Hunter's internal monologue

The Nature of Humanity

The novel explores what it means to be human, especially through Hunter's perspective. He first sees humans as weak. However, Serena's resilience, courage, and ability to love challenge his ideas. Her vulnerability is also her strength, inspiring Hunter to protect her and changing his view of humanity. The story suggests that humanity's true power is not physical strength but emotion, determination, and connection.

“She was so fragile, so breakable, and yet she possessed a strength that could rival any Arum. It was baffling.”
Hunter's observation of Serena

Governmental Control and Secrecy

A major theme is the government's (DOD) role in controlling and hiding aliens on Earth. The DOD manipulates humans and aliens, using Arum like Hunter for its own purposes while keeping the truth from the public. This theme shows the dangers of unchecked power, the ethical compromises made for national security, and the potential for betrayal from authorities. It adds danger and mistrust for the main characters.

“The government wasn't protecting us. They were managing us. And that was a far more terrifying truth.”
Serena's realization

Plot Devices & Literary Techniques

First-Person Dual Perspective

Alternating viewpoints between Hunter and Serena.

The novel is told through alternating first-person perspectives of Hunter and Serena. This device allows readers to gain deep insight into the thoughts, feelings, and motivations of both protagonists. It effectively builds tension, as their individual fears and desires are revealed, and allows the reader to understand their evolving relationship from both sides. This dual perspective is crucial for highlighting their contrasting backgrounds and the internal struggles they face, particularly Hunter's struggle with his Arum nature and his growing feelings for a human.

Inciting Incident (Murder)

Melissa's murder by Marcus ignites the entire plot.

The brutal murder of Serena's best friend, Melissa, by the alien Marcus, serves as the primary inciting incident. This shocking event immediately thrusts Serena into a terrifying new reality, making her a witness and a target. It's the catalyst that forces her to flee and brings Hunter into her life. Without Melissa's death, Serena would never have been exposed to the alien world, and the central conflict and romance would not have occurred. It establishes the high stakes and the immediate danger she faces.

Foil Characters

Hunter and Serena serve as foils to each other.

Hunter and Serena act as foil characters, highlighting each other's distinct qualities and contributing to their development. Hunter is an ancient, powerful alien assassin, cold and detached, while Serena is a modern, ordinary human, emotional and vulnerable. Their contrasting species, experiences, and worldviews create immediate conflict and tension, but also facilitate their growth. Hunter learns empathy and love from Serena, while Serena gains strength and a broader understanding of the universe from Hunter. Their differences make their connection more profound and challenging.

The Unreliable Narrator (Implicit)

Hunter's initial perception of humans is flawed.

While not a traditional unreliable narrator in terms of intentionally misleading the reader, Hunter's perspective at the beginning of the novel is inherently flawed regarding humans. His species' ingrained biases and his training lead him to believe humans are weak, insignificant, and not worth protecting. This 'unreliable' initial judgment sets up his character arc, as his interactions with Serena gradually dismantle these preconceived notions. The reader experiences his changing perspective as he learns to see Serena, and by extension, humanity, in a new, more appreciative light.

Quiz

10 questions on the plot and the characters. Each answer comes with a short explanation.

  1. Question 1

    What genre does the book 'Obsession' primarily fall into?

    1. Fantasy
    2. Mystery and Romance
    3. Science Fiction Thriller
    4. Historical Fiction
    Show answer

    B. Mystery and Romance The provided text explicitly states the genres as 'Mystery, Romance'.

  2. Question 2

    Is 'Obsession' a part of a series that must be read in order?

    1. Yes, it is the third book in the Lux Series.
    2. No, it is a stand-alone novel and a spin-off of the Lux Series.
    3. Yes, it is the first book in the Obsession Series.
    4. It depends on whether you read the Lux Series first.
    Show answer

    B. No, it is a stand-alone novel and a spin-off of the Lux Series. The text clearly states, 'This is a stand alone novel that is an adult spin-off of the Lux Series You do not need to read a Lux book to read Obsession and vice versa.'

  3. Question 3

    What is Hunter's primary occupation?

    1. A scientist working for the Department of Defense.
    2. A detective investigating alien activity.
    3. A ruthless killer employed by the Department of Defense.
    4. A secret agent protecting witnesses.
    Show answer

    C. A ruthless killer employed by the Department of Defense. The text describes Hunter as 'a ruthless killer. And the Department of Defense has him firmly in their grasp'.

  4. Question 4

    What event thrusts Serena Cross into a dangerous new world?

    1. She discovers her best friend is an alien.
    2. She witnesses her best friend's murder by an alien.
    3. She is targeted by the Department of Defense.
    4. She uncovers a conspiracy involving the senator's son.
    Show answer

    B. She witnesses her best friend's murder by an alien. Serena witnesses her 'friend’s murder at the hands of what can only be an alien, thrusting her into a world that will kill to protect their secret.'

  5. Question 5

    What is the main conflict Hunter faces regarding Serena?

    1. He must decide whether to turn her over to the aliens.
    2. He struggles to reconcile his duty to the DoD with his growing feelings for her.
    3. He is tasked with protecting her from his mortal enemy, which goes against his usual job.
    4. He believes she is a threat to the secret alien community.
    Show answer

    C. He is tasked with protecting her from his mortal enemy, which goes against his usual job. Hunter is 'saddled with something he’s never had to do before: protect a human from his mortal enemy.' This task conflicts with his usual duties and his nature.

  6. Question 6

    What characteristic of Hunter is highlighted early in his description?

    1. His kindness and empathy.
    2. His arrogance and domineering nature.
    3. His shyness and introversion.
    4. His meticulous planning and caution.
    Show answer

    B. His arrogance and domineering nature. Hunter is described as 'arrogant, domineering, and... To. Die. For.'

  7. Question 7

    What does Serena initially not believe about her best friend's claims?

    1. That the senator's son is involved in illegal activities.
    2. That the senator's son is secretly working for the aliens.
    3. That the senator's son has supernatural abilities.
    4. That the senator's son is planning to betray his father.
    Show answer

    C. That the senator's son has supernatural abilities. Serena 'didn’t believe her best friend when she claimed to have seen the son of a powerful senator turn into something... unnatural.'

  8. Question 8

    What internal conflict does Hunter experience as he protects Serena?

    1. He is torn between his loyalty to the aliens and his duty to the DoD.
    2. He struggles with whether to reveal the existence of aliens to the public.
    3. He questions his own sanity and the reality of the situation.
    4. He finds himself breaking the rules he has always followed due to his feelings for Serena.
    Show answer

    D. He finds himself breaking the rules he has always followed due to his feelings for Serena. The text states, 'Soon he’s doing the unthinkable—breaking the rules he’s lived by, going against the government to keep Serena safe.' This suggests an internal conflict driven by his evolving relationship with Serena.

  9. Question 9

    According to the text, who or what are potentially the biggest threats to Serena's life?

    1. Only the aliens.
    2. The Department of Defense and the aliens.
    3. The aliens, the government, and potentially Hunter himself.
    4. Her best friend's killer and the senator's son.
    Show answer

    C. The aliens, the government, and potentially Hunter himself. The final question posed in the text is, 'But are the aliens and the government the biggest threats to Serena’s life… or is it Hunter?' This implies Hunter could also be a threat.

  10. Question 10

    What is the significance of Hunter going 'against the government'?

    1. It means he is officially resigning from his position.
    2. It indicates a complete betrayal of his employers.
    3. It highlights the depth of his commitment to protecting Serena, overriding his established protocols.
    4. It suggests he has been secretly working for the aliens all along.
    Show answer

    C. It highlights the depth of his commitment to protecting Serena, overriding his established protocols. The phrase 'going against the government to keep Serena safe' implies that his actions to protect her are contrary to the directives or expectations of his employers (the government/DoD), demonstrating a significant shift in his priorities and actions.

Obsession FAQ

Is "Obsession" by Jennifer L. Armentrout a standalone novel?

Yes, "Obsession" is a standalone novel. You do not need to have read any books from the Lux Series to enjoy or understand this story, nor is it required to read "Obsession" before starting the Lux Series.

What genre is "Obsession" by Jennifer L. Armentrout?

The book "Obsession" falls into the genres of mystery and romance. It features thrilling suspense alongside a strong romantic element.

Who are the main characters in "Obsession"?

The main characters are Hunter, a ruthless killer working for the Department of Defense, and Serena Cross, a woman who witnesses a murder and is thrust into a dangerous secret world.

What is the basic premise of "Obsession"?

Hunter, a trained operative, is tasked with protecting Serena Cross from his mortal enemy after she witnesses an alien murder her best friend. This assignment forces him to break his rules and go against his superiors to keep her safe.

Is "Obsession" related to the Lux Series?

Yes, "Obsession" is an adult spin-off of Jennifer L. Armentrout's Lux Series. While it shares a universe, it is designed to be read independently.

What kind of relationship do Hunter and Serena have?

Hunter and Serena have a complex relationship marked by initial conflict and undeniable attraction. Despite their vastly different worlds and Hunter's dangerous nature, they develop a strong romantic connection.

What kind of threats do the characters face in "Obsession"?

The characters face multiple threats, including ruthless aliens who want to protect their secret, the government that employs Hunter, and potentially Hunter himself as he struggles with his own nature and the rules he must break.

Is "Obsession" suitable for mature readers?

Yes, the description indicates it is an "adult spin-off" and features themes of danger, violence, and romance that are geared towards a mature audience.

What makes Hunter a compelling character?

Hunter is described as arrogant and domineering, but also a highly skilled and ruthless killer. His internal conflict between his duty and his growing feelings for Serena makes him a complex and compelling figure.

What motivates Serena to get involved in the central conflict?

Serena is drawn into the conflict after witnessing the murder of her best friend by what she describes as an "unnatural" being. This traumatic event forces her to confront a hidden world and rely on Hunter for protection.

About the author

Jennifer L. Armentrout

Jennifer L. Armentrout

Jennifer L. Armentrout is a contemporary author known for her works in the young adult and new adult fiction genres. Some of her notable books include "Onyx," "Wait for You," "Wicked," "The Problem with Forever," "From Blood and Ash," and "Every Last Breath." Her writing often features elements of romance, fantasy, and suspense.

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