The Girl in the Pool ending explained: Who murdered Hannah?

The Girl in the Pool is a thriller mystery film that got its theatrical release on July 26, 2024. Directed by Dakota Gorman, the movie interweaves a set of very well-crafted characters. The Girl in the Pool is a must-watch for anyone wanting to keep the mystery till the very end. The well-executed plot in The Girl in the Pool brings new expectations to the genre of independent thriller movies.

The Girl in the Pool has a set of very talented cast including Freddie Prinze Jr. , Gabrielle Haugh, Monica Potter, Tyler Lawrence, Brielle Barcusca, and Kevin Pollack. Freddie and Monica last appeared together on the screen back in 2001 in Head Over Heels. This time in The Girl in the Pool, they appear as a middle-aged couple who share lots of silence.

The Girl in the Pool is about Tom, a wealthy man who has been having an affair with a woman, Hannah, unbeknownst to anyone else. But things take a sudden turn when he finds Hannah murdered in his pool on his birthday.

Tom's troubles get further complicated when he finds that his wife, Kristen, has thrown a surprise birthday party for him. This leads to Tom committing a series of mistakes to hide the murder. Except for Tom, no one at the birthday party knows that there is a dead body hidden right under their eyes. This gives rise to a very tense environment, where the audience is constantly in anticipation about the mystery getting out, keeping them on the edge of their seats.

Hannah gets killed. (Image via Apple TV)

The birthday party turns into a game of hide and seek, where it seems like everyone is hiding something.

*Disclaimer: The article is written completely from the author's perspective. This article also contains spoilers from the movie '**The Girl in the Pool.' Reader's discretion is advised.*

What happens on Tom's birthday in The Girl in the Pool

At the beginning of The Girl in the Pool, we see Tom being very stressed about something. He finds himself lost in something, but we realize that deep beneath it there are roots of fear. He has committed a very serious crime and has no idea how to fix it. Slowly, in flashbacks, we realize that Tom, a married man, has been having an affair with a woman. It is Tom's birthday that day and his wife, Kristen, invites him out for dinner. We see that Tom finds it unbearable to hide some dark, mysterious incident that happened to him in the morning.

In the flashbacks, we see that earlier that day, his mistress Hannah had snuck into his house to wish him for his birthday. Tom agrees to spend an hour with her, and together they go to his backlot, where he pushes her into the pool, and the two start to get intimate.

Aiden catches them on drone. (Image via Apple TV)

Soon, Tom notices that a neighbor's drone is spying on them and has recorded them together. Angrily, Tom rushes out to find the neighbor's boy, Aiden, to sue him for spying. However, the boy threatens to expose his secret, and so Tom returns home without saying anything.

But when he reaches the pool, he is in for a devastating shock. Tom finds that someone has killed Hannah by smashing her head in. He sees her body floating on the surface of the blood-covered pool. He has no idea who has killed her but decides to clean the entire scene before Kristen reaches home.

Kristen tells Tom on the phone that she will reach home in half an hour. He manages to clean the entire crime scene, keeps Hannah's body inside a box with her belongings, and takes a shower to rid himself of the smell of blood before she arrives.

Kristen arrives and tells Tom to get ready for dinner, but then reveals that she has a big surprise for him. As the curtains are open, Tom sees that Kristen has invited all their friends and relatives to their home for a party. This now becomes a bigger challenge for Tom as he has to keep any hints of the murder hidden from everyone at the party.

Kristen's father, Frank, is a clever man who notices some suspiciousness behind Tom's behavior. He believes that Tom has been hiding something from everyone, and wants him to confess it before his wife. Soon, we also find out that Tom has a very strained relationship with Kristen, and that their marriage is on the verge of breaking up.

Alex and Rose start to ask questions. (Image via Apple TV)

This has deeply affected their children, Rose and Alex. Rose has been living away from the family with her Hawaiian boyfriend and wants to drop out of school to work for an NGO. Meanwhile, Alex is a silent young man who wants to do anything to keep his parents together.

Tom agrees to keep his nerves down and go through the party for the sake of his family. But soon his friends encourage him to drink alcohol and smoke pot which heightens his senses. This is worsened by a stranger arriving at the party - one who may need some answers.

Who killed Hannah in The Girl in the Pool ?

Tom tracks the stranger. (Image via Apple TV)

Tom notices a stranger spying on him throughout the party. Soon, he discovers that Kristen is talking to the man. When questioned, she introduces him as Kevin. Kevin was looking for his wife because her last Uber location was showing at Tom's house. Tom soon realizes that Kevin is Hannah's husband, and that he was the one calling her phone before Tom switched it off.

Tom remembers that Hannah had mentioned Kevin during their conversations and how he would be mad if they were exposed. Tom soon begins to develop a suspicion that Kevin has murdered Hannah during the time Tom went out to catch the kid's drone. An enraged Tom tries to threaten Kevin into telling the truth.

Kevin (played by Rushi Kota) in The Girl in the Pool. (Image via Apple TV)

Upon interrogation and after threatening him with a gun, Tom realizes that Kevin is not the murderer. Tom also realizes that he has exposed all of his secrets in vain. Kevin runs to call the police but Tom catches him and knocks him unconscious with the gun. His son Alex catches Tom tying up Kevin's body.

Tom pursues his son to tell him to not reveal the secret, but then the story takes an unexpected twist. Alex confesses that he knows everything. He is the one who killed Hannah in the morning. Alex had arrived home early and saw his father getting intimate with another woman. Tom went out to catch the drone and saw Hannah all alone. Enraged, Alex grabbed a baseball bat, went to the pool, and smashed her head multiple times. She fell dead in the pool immediately.

Alex kills Hannah in The Girl in the Pool. (Image via Apple TV)

Tom finally realizes that the murderer is his son. At this point, Kristen and Rose arrive at the scene and find Kevin tied up. Kristen reveals that she already had some idea about the affair, and was talking to a lawyer for a divorce. Tom tells the other three people to go outside and send the invitees home. By that time, he would try to clean up the scene.

Tom comes outside the house after some time, greets everyone, and ends the party with a farewell speech. Soon the house is surrounded by police cars. We realize that while he was inside, Tom had called the police confessing that he had murdered Hannah, saving Alex from getting arrested.

Tom surrenders himself to the police. (Image via Apple TV)

In the end, Tom is taken by the authorities into the car. Tom sets things right by sacrificing himself for his family.

The Girl in the Pool is a thriller movie that keeps the viewers glued till the very end. The movie ends on an emotional note with Tom sacrificing for Alex's sake, finding redemption for his mistakes by giving his son a new life.