The film stars Jennifer Love Hewitt, Sarah Michelle Gellar, Ryan Phillippe and Freddie Prinze, Jr., with Anne Heche, Bridgette Wilson, and Johnny Galecki appearing in supporting roles. I Know What You Did Last Summer centers on four friends who are being stalked by a killer, one year after covering up a car accident in which they were involved.
On the Fourth of July in Southport, North Carolina, senior high schooler Julie James, her boyfriend Ray Bronson, her best friend Helen Shivers, and Helen's boyfriend Barry Cox are all driving home from Helen's queen coronation at the Croaker beauty pageant. Along the road, they accidentally hit a pedestrian. Max, who has a crush on Julie, stops by but is convinced to leave. After some arguing, the group decides to dispose of the body. However, the man awakes while they're tossing him into the sea. Shocked, the group agrees to never again discuss what had happened.
One year later, a disheartened Julie is home from college for the summer. She and Ray have broken up, and Julie, once a model student, has been failing exams all year. She receives a letter with no return address, stating, "I know what you did last summer." Julie informs Helen, who works at her family store and feels similarly dispirited. They take the note to Barry, who immediately thinks Max responsible. They go to the docks, where Max works, and Barry threatens him with a hook. Julie meets Ray who's now working as a fisherman; he tries to reconcile with her, in vain. Later, Max is killed by a figure in a rain slicker wielding a hook. Barry discovers a note in his gym locker saying "I know." His jacket is stolen and he's almost run over by the slicker guy driving Barry's car.
Helen and Julie, who had previously learned their victim was identified as one David Egan, visit Missy, David's sister. Missy tells them that a friend of Davis's named Billy Blue also visited her.
Later, the killer sneaks into Helen's house, cuts off her hair while she sleeps, and writes "Soon" on her mirror. Julie finds Max's corpse wearing Barry's jacket in the trunk of her car. When she calls the others, the body is missing. Ray claims to have received a threatening letter, too. Helen rides with Barry as the reigning Croaker Queen in the Fourth of July parade; they notice a man wearing a slicker, Barry chases him, but it turns out to be a red herring.
Julie goes back to Missy, who reveals David allegedly committed suicide, out of guilt for the death of his girlfriend Susie in the crash of the car David was driving. Missy shows David's suicide note to Julie. As the writing matches that of the note she received, Julie realizes it wasn't a suicide note but a death threat. At the Croaker Pageant, Helen witnesses Barry being murdered on the balcony. She rushes up there with a police officer but finds no sign of the killer or Barry.
While driving Helen home, the officer is stopped by a stalled truck, then killed by a dark figure with a hook. Helen rushes to her family's store, the killer follows her inside and kills Helen's sister Elsa. Helen manages to flee, but the killer chases her into an alley and slashes her to death, her screams drowned out by the noise of the parade.
Julie finds an article mentioning Susie's father, Ben Willis, and realizes it's Ben the one they ran over, right after he had killed David to avenge his daughter. She at goes to the docks to tell Ray, who's skeptical. Julie notices Ray's boat is called "Billy Blue" and runs away before Ray can explain that he went to see Missy to relieve his conscience. Ben shows up, knocks Ray out and invites Julie to hide on his boat. Looking around, she finds photos and articles about her and her friends, and pictures of Susie. Ben's boat leaves the docks, as Ray regains consciousness and steals a motorboat to rescue Julie, who's being chased all around Ben's boat. Ray ultimately uses the rigging to sever Ben's hook-carrying hand and send him overboard. When the police question them, they deny knowing why Ben attempted to kill them, but they're relieved not to have actually killed anybody the previous summer, and reconcile.
A year later, Julie is in college in Boston. As she enters the shower, she notices the words "I still know" on the mirror. Moments later, a dark figure crashes through it.Jennifer Love Hewitt as Julie James
Sarah Michelle Gellar as Helen Shivers
Ryan Phillippe as Barry Cox
Freddie Prinze Jr. as Ray Bronson
Bridgette Wilson as Elsa Shivers
Anne Heche as Missy Egan
Muse Watson as Ben Willis
Johnny Galecki as Max Neurick
The film produced two soundtracks. One of them featured the score composed by John Debney, while the other contained various rock songs found in the film.
- "Hush" by Kula Shaker (2:55)
- "Summer Breeze" by Type O Negative (4:57)
- "D.U.I." by The Offspring (2:26)
- "Kid" by Green Apple Quick Step (3:17)
- "This Ain't the Summer of Love" by L7 (3:09)
- "Losin' It" by Soul Asylum (3:01)
- "Hey Bulldog" by Toad the Wet Sprocket (2:31)
- "My Baby's Got the Strangest Ways" by Southern Culture on the Skids (3:59)
- "Waterfall" by The Din Pedals (3:47)
- "Clumsy" by Our Lady Peace (4:27)
- "One Hundred Days" by Flick (3:40)
- "Great Life" by Goatboy (3:50)
- "2 Wicky" by Hooverphonic (4:44)
- "Don't Mean Anything" by Adam Cohen (3:43)
- "Proud" by Korn (3:17)
The film received mixed reviews upon release, inevitably drawing both positive and negative comparisons to Scream, also written by Williamson. Mick LaSalle thought it inferior to 'Scream', but Richard Harrington compared it favorably, stating that it was "...a smart, sharply drawn genre film with a moral center and a solid cast of young actors to hold it." Variety was also enthusiastic, calling it a "polished genre piece with superior fright elements that should perform at better than average theatrical levels." On Rotten Tomatoes, 35% of reviews were positive. Metacritic reported an aggregate score of 52 out of 100 based on 17 reviews. Critic Roger Ebert gave the film 1/4 stars and wrote in his review, "The best shot in this film is the first one. Not a good sign."
Jennifer Love Hewitt was praised for her performance as Julie James by an Entertainment Weekly columnist stating that Hewitt knows how to scream with soul.
In its opening weekend the film grossed $15,818,645 in 2,524 theaters in the United States and Canada, ranking #1. By the end of its run, I Know What You Did Last Summer grossed $72,586,134 domestically and $53 million internationally for a worldwide total of $126 million.
The film was released on DVD by Columbia TriStar Home Entertainment in the US on June 16, 1998. Special features included a theatrical trailer and filmmaker's commentary. It was released on DVD & video in the UK by Entertainment in Video with no special features. The film was released on Blu-ray for the first time ever on July 22, 2008, with more special features including the director's short film: "Joyride" with optional commentary, a featurette titled "Now I Know What You Did Last Summer", a music video of Hush by Kula Shaker and also included the theatrical trailer and filmmaker's commentary from the DVD. Though it was released in the US, it is available to be watched in regions A, B & C. The Blu-ray was re-released by Mill Creek Entertainment on September 30, 2014 in the US. It contains no special features and is only available in Region A.
The film was followed by two sequels: I Still Know What You Did Last Summer (1998) and I'll Always Know What You Did Last Summer (2006), which went direct-to-video. Both were critically panned. In the first sequel, Jennifer Love Hewitt, Freddie Prinze Jr. and Muse Watson reprise their roles. The second sequel has very little relation to the first two, other than the premise, the villain, and the producers. It featured new characters and a different setting.
On September 14, 2014 Sony reported that they have plans to remake the film; Mike Flanagan and Jeff Howard are writing a script. In a June 1, 2016 Blumhouse.com "Shockwaves" podcast, writer Mike Flanagan revealed and further confirmed this new iteration and re-imagination of the franchise would not have any inventions of the Lois Duncan novel (the antagonist being a central character) nor the 1997 feature (the fisherman Ben Willis and 4 primary protagonists Julie James, Helen Shivers, Barry Cox, and Ray Bronson). Further, the new direction and scope of the film necessitates an estimated budget of $15–20 million. Sony also states that the film is a high priority and is set for a release somewhere between 2017-2020.