The film begins with a group of four friends – Julie James (played by Jennifer Love Hewitt), Helen Shivers (played by Sarah Michelle Gellar), Barry Cox (played by Ryan Phillippe), and Ray Bronson (played by Freddie Prinze Jr.) – celebrating their high school graduation in the coastal town of Southport, North Carolina. While driving along a secluded road, they accidentally hit a pedestrian with their car.
In a panic, the friends decide to cover up the accident and dispose of the body in the nearby ocean. They make a pact to never speak of the incident again and go their separate ways, believing that they have gotten away with murder.
One year later, as the group reunites for the Fourth of July holiday, they begin receiving mysterious and threatening messages alluding to their dark secret. They soon realize that someone knows what they did last summer and is intent on seeking revenge.
As the friends are stalked by a mysterious figure wearing a rain slicker and wielding a hook, they must confront their guilt and unravel the identity of their tormentor before it’s too late. Along the way, they uncover shocking revelations about the victim they thought they had killed and the true nature of the events that transpired that fateful night.
As the body count rises and the killer closes in, Julie and her friends race against time to stop the bloodshed and confront their own demons. They must confront the consequences of their actions and face the brutal reality that their past sins have come back to haunt them.
In a climactic showdown, Julie confronts the killer and discovers that it is actually Benjamin Willis (played by Muse Watson), the father of the man they accidentally killed. Seeking vengeance for his son’s death, Willis has been systematically targeting Julie and her friends in a twisted game of cat and mouse.
In a tense and thrilling confrontation, Julie manages to outwit Willis and defeat him, ultimately surviving the ordeal. The film ends with Julie returning home, haunted by the events of the past year but determined to move on with her life.
“I Know What You Did Last Summer” is praised for its suspenseful atmosphere, clever twists, and memorable performances. It became a commercial success upon its release and spawned several sequels, cementing its status as a classic of the slasher genre.