The Girl in the Pool Ending, Explained: Who Killed Hannah?

In the murder mystery, ‘The Girl in the Pool,’ directed by Dakota Gorman, Thomas, also known as Tom, finds himself at the center of a complex web of deception after his mistress, Hannah, is murdered in the backyard swimming pool moments before his birthday party takes off in the family house. As family, friends, and neighbors pour into the premise, the protagonist is pulled into an endless mess as the potential fallout from his actions wreaks havoc upon his psyche. During the party, Tom has to contend with constant arguments with his wife Kristen, his daughter Rose, and the nervous disposition of his son Alex, who is fearful that his parents might divorce.

Further complications arise when his father-in-law, William, clarifies that he does not support Tom’s behavior and how he treats his wife. With numerous avenues of disruption, the protagonist tries to survive the party throughout the day and night while keeping his infidelity and the dead body in his backyard a secret. Everything moves according to plan until a stranger shows his face at the house looking for Hannah, forcing Tom to take drastic actions that ultimately lead to the conclusion of the twisted narrative! SPOILERS AHEAD.

The Girl in the Pool Plot Synopsis

On his birthday, Tom, a married affluent man who lives in a posh suburban home with his wife and two children, is visited by his mistress, Hannah, a few hours before his family shows up. Conflicted, the protagonist welcomes her in and spends some time with her playfully in the backyard swimming pool, a series of events that eventually leads to them having sex. The neighbor kid, Aiden, records Tom and Hannah’s affair using a drone he flies around the house constantly. Angry, Tom goes out to confront the kid, only to return to the pool and find Hannah’s bloodied body floating in the pool’s water.

Frightened that if he reports the crime, his infidelity will become well-known, Tom decides to hide Hannah’s body in the backyard bin. After learning that his wife will be home soon to celebrate his birthday, the protagonist sets about removing any evidence of Hannah’s presence in the house – scrubbing mirrors and cleaning her blood. Soon, his wife arrives and unveils an outdoor house party for Tom, which takes him entirely by surprise. Unbeknownst to him, Kristen has been preparing for months for the event while he is in a state of panic because of the early morning events.

As the party takes off, Tom’s actions become driven by paranoia as allegations are brandied against every family member. His constant bickering with his wife, father-in-law, children, and friends leaves him ragged and suspicious of who he can trust. After several close run-ins, Tom’s worst nightmare is realized when Kevin, Hannah’s husband, shows up at the party looking for his wife. Tom is triggered by Kristen conversing with the man in a friendly manner. When avoiding the issue no longer works, he decides to take matters into his own hands and threatens Kevin with a gun, believing that he is the perpetrator behind Hannah’s murder.

The Girl in the Pool Ending: Did Kevin Kill Hannah?

From the moment Kevin sets foot in the house, Tom is instantly wary of him even though he has no clue about the man’s association with Hannah. The protagonist finds his presence unnerving, and given the psychological factor of Hannah’s dead body lying in his backyard, he is understandably distressed that an unknown entity is infringing on his hospitality. However, after learning that Kevin is, in fact, Hannah’s husband, someone he has heard only bad things about from his mistress’ mouth, he postulates that he had a part to play in her death. However, this ultimately turns out to be a false claim as the killer’s identity lies somewhere else.

There are several reasons for Tom to suspect Kevin as the murderer. For one, Hannah often told him that if her husband came to know about her infidelity, she was fearful of what he might do as a result of the knowledge. This one-sided perspective from her makes Tom form a picture of Kevin even before he meets him, and a negative one at that. Thus, when he threatens him at gunpoint, Keven reveals that he is nothing like what Hannah painted him to be. From Tom’s perspective, the husband is a domestic abuser and someone who regularly beats his wife. While he has no evidence to show for these claims, he believes them because of Hannah’s words.

Additionally, as Tom cleans any leftover remains of Hannah’s presence from the home premises, he finds repeated calls being left on Hannah’s phone from Kevin. The numerous phone calls further add to Tom’s perception of Kevin as someone who is always monitoring his partner and tracking her movements like a jealous ex. As a consequence, the multitude of observations about Kevin’s behavior leads him to think that he is most likely the killer, owing to his obsession with his wife and how upset he might have felt upon learning that she was cheating on him with someone else. 

However, it is also possible that Tom, who is under the influence of drugs and alcohol, is in a heightened state of emotion that clouds his better judgment and his inhibition. Hence why, he uses the gun from his storage to threaten Kevin, a drastic measure that he had not thought out properly because of the magnitude of the crime engulfing him. While Tom is unable to prove with any certainty that Kevin is the murderer, he believes it to be so until his son suddenly stumbles into the room. It is at this point the real killer’s identity is revealed, and Kevin is absolved of any role in Hannah’s death.

Who Murdered Hannah?

Although Tom is relentless in his assumption that Kevin is Hannah’s murderer, he is stunned to learn that the actual killer is his son, Alex, who walks in on his father while he has Kevin tied in ropes. Desperate to clear his name, he half-explains to Alex the reasons behind his actions while pleading with him to trust that he is doing the right thing to ensure the family’s safety. It comes as a shock to the protagonist, therefore, when Alex, of his own volition, reveals that the man in ropes had nothing to do with Hannah’s death – instead, it was him. Alex had bashed Hannah on the head with a baseball bat, which ultimately caused her death.

Throughout the narrative, Alex presents an insecure exterior, concerned about his parents’ welfare and their likelihood of splitting, given their constant arguments and bickering. While it acts as a brief insight into his turbulent childhood and how helpless he feels when witnessing the adults in the household drifting away from one another, it also alights upon his reasons for murdering Hannah. The boy had seen his father and Hannah engaging in their affair earlier that morning through his hiding place in the bushes. While the knowledge that his father was cheating on his mother was traumatizing enough, he was also apprehensive about them divorcing and him potentially growing up in a broken home as a result.

Enraged and embittered, he turned his aggression towards Hannah, who he believed was why his father was no longer as close to his mother. When Tom left the backyard to scold Aiden for spying on him and Hannah, Alex headed straight to the swimming pool with a baseball bat, striking the woman on her head as soon as she surfaced from the water. After delivering the killing blows, Alex hid the murder weapon in the bushes and came back at the same time as everyone else to celebrate his father’s birthday party. However, instead of being concerned about his role in her death, he was more worried about Tom and Kristen’s strained relationship, constantly pleading with his father not to divorce.

Tom’s entire world shatters when he realizes how deeply poisoned his whole family has become because of his actions. His infidelity has corrupted everyone around him, most of all his son, who is now a murderer because of him. This unforeseen twist of events finally brings Tom back to Earth as he contemplates the best course of action to ensure his family’s survival, even if it costs him his soul.

Did Thomas Take the Fall?

For large parts of the narrative, Tom acts selfishly only to serve his interest, which is to absolve himself of any guilt in Hannah’s death and to brush his infidelity under the carpet if he can. Consequently, he often butts heads with Kristen, who has spent months preparing his birthday party, but he acts ungratefully towards her, pushing her even further. He is so wrapped up in his own issues that he does not quite realize its impact on those close to him, specifically his wife and children. However, Alex’s involvement in Hannah’s murder finally opens his eyes for the first time in a long time. Concerned that his son would pay the price for his sins, Tom gives himself over to the police, assuming the blame for Hannah’s murder.

The film’s ending depicts a monumental shift in Tom’s character, who has radically changed his outlook. When the party begins, Tom is worried that he might be implicated in the crime, destroying all the success he had built up over the years. Even during his clashes with his family, friends, and father-in-law, he remains defensive and never assumes any blame for his mistakes. On the rare occasion that he does, he does not assume responsibility for those shortcomings, a character flaw that ultimately comes to bear down on him horrifyingly.

Thus, it takes a murder in his backyard for Tom to finally connect the dots and figure out what his real problem is. It is not just the dead body of his mistress in the backyard; it is also his inability to front up and face the consequences of his misdeeds like any accountable person would. When faced with the prospect of Alex being sent away to prison, Tom is no longer confused about what he has to do, as the thought of losing his son is a greater affront to his soul, especially if it comes as punishment for something he did. Therefore, he concocts a noble lie to save his family, showcasing how much he has grown and what is required of him as a father and husband who puts his family ahead of all other priorities in his life, something he has failed to do on previous occasions.

Read More: The Girl in the Pool: Is the Movie Based on a True Story?

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