I Know What You Did Last Summer ending explained: Why the killer strikes again and who survives, explored

The new I Know What You Did Last Summer sequel ends with a shocking twist,raising questions about what’s next for the slasher franchise.

The 2025 film seemingly brings back the premise of the eponymous 1997 film. It also shows a group of friends being hunted down by a hook-wielding killer for their connection to a murder from a year before. So, like before, the friends must protect themselves while relentlessly being hunted by a hooded figure.

The film drops a few red-herring suspects along the way while leading to a twist reveal toward the end. With that in mind, the ending of I Know What You Did Last Summer reveals Stevie as a killer — and so is Ray. They are overwhelmed by their past traumas.

Danica and Ava seemingly survive in the end, but they might run back into Stevie, teased by a post-credit scene that features Karla from the 1998 film.

Disclaimer: This article contains spoilers and mentions of s*icide and emotional trauma. Readers' discretion is advised.

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What is I Know What You Did Last Summer 2025 about?

Danica (Madelyn Cline), Ava (Chase Sui Wonders), Teddy (Tyriq Withers), Stevie (Sarah Pidgeon), and Milo (Jonah Hauer-King) run away after a fatal accident and try to cover it up. A year later, a masked killer starts sending them notes, threatening to expose them.

The killer snatches Wyatt’s life with a deadly hook, leaving Danica to grieve his loss. It’s a brutal reminder that their past is catching up with them. So, they must confront their darkest fears while trying to find who is trying to destroy their lives. Julie (Jennifer Love Hewitt) and Frank (Freddie Prinze Jr.) are pulled back into this chaos.

It all rings all too familiar to them, since they were the only two survivors from the 1997 Southport massacre. So, the new Gen-Z group seeks their help. Once again, the franchise proves that things might be stranger than fiction in Southport. It upends the so-called urban legends, rooting the killers’ motives in deep-seated traumas.

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Who is the killer fisherman?

At the end of the I Know What You Did Last Summer legacy sequel, Stevie and Ray are revealed to be the killers. They both want to hold the group accountable for their horrific actions. That’s why they go on a murder spree.

Why Stevie? That’s because she can't escape her guilt over what happened to Sam.

Stevie cannot get over her guilt about letting Sam be left stranded with no help. It eats her up to the point she contemplates s*icide. However, she eventually decides to turn the hook toward her friends. In the final climactic moments, she seemingly says:

“Why would I kill myself when I could just kill all of you?"

Her trauma festers into rage, driving her to kill. Then, how is Ray involved? Wasn’t Ray helping the friends? Well, the reason Ray turns from a former survivor to a new killer is because of his close bond with Stevie. That’s why he helps Stevie seek retribution from her friends. Yet, there’s more to it.

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What does the ending mean for the franchise?

The ending of I Know What You Did Last Summer shows how trauma manifests itself in a person’s mind and how it can lead someone to do unimaginable things. Ray resents how quickly the town forgot what he and his friends survived.

Ray’s PTSD from the 1997 and 1998 massacres changes his outlook. This time, he is out for blood — for those who wronged him (Grant Spencer) or Stevie. Stevie’s remorse brings her into a similar headspace.

Danica and Ava try to run away from their past, but that doesn’t help them. It’s only when they confront their trauma that they can truly feel free. In the final moments, the two are seemingly the only survivors despite their injuries, since they are rushed to the hospital. Ray dies at Julie’s hands.

The post-credit scene of I Know What You Did Last Summer shows Julie meeting Karla (Brandy). Karla is her former roommate and a fellow survivor from the 1998 massacre. It indicates that the new film may not be just a legacy sequel, but a step in the direction of a franchise reboot — with Stevie’s probable return as the killer.