I Know What You Did Last Summer (2025) ending explained: Who were the real killers?

The conclusion of I Know What You Did Last Summer (2025), a sequel to the late 90s classics, finally provides much-needed answers. Based in the seemingly peaceful town of Southport, the plot involves a new set of teenagers coping with the consequences of an accidental death that plagues their lives. The film also features characters from the prequel, Julie James and Ray Bronson.

Spoiler Ahead: This article includes spoilers for I Know What You Did Last Summer (2025).

As I Know What You Did Last Summer (2025) progresses, a masked killer targets the group, and a pressing question remains: Who are the real killers behind the recent murders? The answer is a shocking one: two individuals, Stevie and Ray, were behind the murder.

This twist changes everything, reshaping the story’s dynamics and its emotional core. In the end, only a few characters survive the deadly events, including Julie, Ava, and Danica.

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Mystery behind the killers in I Know What You Did Last Summer

I Know What You Did Last Summer initially keeps the identity of the murderer unknown, focusing suspicions on various characters. At the centre of the movie is Sam, a young man whose accidental death a year ago gets the movie rolling.

Sam was unintentionally killed by the main group of teenagers during a reckless incident, an event they tried to cover up to avoid legal consequences. This secret haunts them as they return to Southport, unaware that Sam’s death has sparked a dangerous cycle of revenge.

In the final act, it becomes clear that two individuals are responsible for the recent murders: Stevie, a new character who was closely connected to Sam, and Ray Bronson, a returning character from the original film. Stevie’s motivation is rooted in her grief and anger over Sam’s death.

She didn't realize at first that Sam was the victim, but once she found the truth, she became intent upon punishing those involved in Sam's death. Her actions throughout the movie indicate this personal crusade.

The other killer, Ray, who is initially presented as a mentor and friend to the young characters, is finally shown to be in league with Stevie. He becomes involved when Ava happens upon Ray and finds he bears a wound of the type one given to the killer that revealed his involvement.

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Why does Ray turn into a killer?

Ray's turn is important in determining the film's climax. Famous for being a survivor and a loyal figure in the original movie, he appears to provide protection and guidance at first to the younger characters. But as the events unfold and Stevie reveals the truth behind the unintentional death, Ray's intentions become sinister.

He tells Julie that he gave Stevie's parents his word to take care of her. Discovering what became of Sam only serves to frustrate and anger Ray, not only the teens responsible, but also the town in general, for appearing to move on without really examining its dark past.

Rather than finding closure, he joins Stevie on a deadly crusade to exact revenge on those accountable. His journey involves a dramatic confrontation, in which Ava steps in and ultimately dispatches him with a spear gun, ending his revenge campaign.

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Who is left alive after the confrontation?

The movie ends with some of the characters surviving the confrontation. Among them, Ava and Danica survive even after being wounded. They receive medical treatment, and even Julie survives the confrontation.

Stevie’s fate, however, remains uncertain. Ray insists that he killed her, but Ava doubts this, pointing to the possibility that Stevie may have escaped. The film does not confirm her death, choosing instead to leave her future open-ended.

Still, the ending doesn’t linger on this ambiguity. Instead, it centers the narrative on those left behind and the emotional burden they now carry. I Know What You Did Last Summer (2025) ending has a definitive conclusion to the mystery while accepting that trauma has long-lasting consequences for the people involved.

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