A group of teenagers in Colorado find themselves being stalked and killed one by one by a mysterious figure with a hook, exactly one year after they covered up a friend's accidental death.
On July 4th, in the small Broken Ridge, Colorado, the teenagers Colby, his girlfriend Amber and their friends Zoe, Roger and PJ play a prank with the legend of the Fisherman that kills teenagers with dirty little secrets with his hook in an entertaining park. However, when PJ jumps with his skateboard, there is an unexpected accident and PJ dies. The group stays together and makes a covenant to keep their secret. One year later, Amber receives 50 messages in her cell-phone saying "I Know What You Did Last Summer" and she gathers her friends to find who might have told about their pact. They find that PJ's cousin Lance also knows what they did. Sooner they find that a dark man wearing slicker is chasing them with a hook to kill each one of them.—Claudio Carvalho, Rio de Janeiro, Brazil
A group of teens accidentally kill a fellow friend in a 4th of July prank. They all band together and decide to take there secret to the grave. Little do they know that they really will be taking there secret quite literally to the grave as one year later there secret comes back for revenge. Can they work out who's killing them off one by one or will they all take there secret to the grave.—Nathan Bradley
A group of teenagers in a Colorado find themselves being stalked and killed one-by-one by a mysterious figure with a hook, exactly one year after they covered up a friends' accidental death...—Anonymous
After the accidental death of a friend during a dangerous prank, a group of friends decide to cover-up his death and act as if they didn't see anything (knowing that his Sheriff father will make sure they do time). However, one year passes and the friends are having their fair share of problems and haven't been together for a while. But they are soon bought together when somebody sends a lot of intimidating messages saying 'I Know What You Did Last Summer' and begins making the teens' lives hell. Soon, the friends find themselves being murdered one-by-one by a mysterious figure in a slicker and with a large hook as a weapon...—Anonymous
In a small Colorado town, Amber Williams (Brooke Nevin), her friends Zoe (Torrey DeVitto) and Roger (Seth Packard), and her boyfriend Colby Patterson (David Paetkau) stage a prank at the town carnival, with Roger faking the return of the "Fisherman" killer. However, their friend P.J. Davis (Clay Taylor) is accidentally killed during the stunt, and to cover up what happened they burn the evidence and make a pact that the secret will die with them.
One year passes after the group separates, and Amber returns to town to discover that Colby never left to pursue his college scholarship. She leaves the party angry, and goes up to the mountains where she encounters one of the officers who witnessed the accident, Deputy Haffner (K.C. Clyde).
Later that night, Amber awakens to a sound, and receives 50 text messages reading "I know what you did last summer". She drives to Zoe's shack to find her band rehearsing for a concert, and after Amber apologizes for not contacting her, Zoe allows her to sleep there for the night.
The next day they find Roger fixing ski-lifts gondolas; he angrily sends them away when they inform him someone knows what happened. Zoe goes to find Colby working as a lifeguard at a public pool; he dismisses her then returns to his post to find "I know what you did last summer" written in the ground. Amber is attacked on a ski-lift by someone wielding the hook, but Colby doesn't believe her.
Later that night, a drunken Roger contemplates suicide while pulling out the hook from the prank, which he had salvaged from the fire. He investigates a noise when he is attacked by the Fisherman, who slits his throat after a chase. Colby goes to Lance and Zoe telling them that he believes them, so they go to warn Roger again but find him dead along with a suicide note and the hook. Deputy Haffner strangely shows up wielding his gun at them, accusing them of the murder, until he reads the suicide note.
After their statements, they return to Amber's house to find pictures of them from the high school yearbook sliced up and stuck to the wall reading "SOON". They all stay at Zoe's place again and find Lance (Ben Easter) outside, who shows them a message engraved on his motorbike, and they agree to stay together for safety. Colby goes to the pool to do some laps after his shift, and is hooked in the ankle by the Fisherman, who disappears.
The night of Zoe's concert, Amber and Lance stick together while Colby, who is now on crutches, sneaks off to get drunk. The Fisherman swings his hook at Colby but misses; Colby grabs a large butcher knife and stabs the Fisherman in the back, but he appears to be completely unharmed. The Fisherman eventually breaks through a window and hooks Colby in the mouth. Amber and Lance go back to congratulate Zoe but are attacked. Zoe breaks away and is stabbed in the stomach and then thrown over a balcony. As Amber and Lance make their way up to the balcony to find Zoe's corpse, P.J's father, the sheriff, comes in and finds Amber covered in blood. He assumes they committed the murders, but he gets pulled into the darkness and hooked to death.
Outside, Deputy Haffner arrests Amber and Lance and escorts them to the back of his jeep; in the back lies Zoe's body. The Fisherman appears and makes his way towards Haffner, who fires several times, but the Fisherman doesn't budge and impales Haffner on a forklift.
Amber and Lance get into the car and run the Fisherman down, but he immediately gets up and takes his mask off, revealing the decomposed face of Ben Willis, the undead man who brutally committed the original murders 10 years ago. He then immediately disappears into thin air. Amber and Lance go to get help but are again attacked by Willis and are chased into a warehouse. They make it out and lure Willis into a thresher, which appears to kill him.
A year later, Amber is driving across the desert, talking to Lance as a tire blows out. She stops in the middle of nowhere and waits while she talks to Lance. She stands in the middle of the road, and looses reception. Which ultimately interupts her conversation with Lance; Amber then begins looking around as the camera cycles around her, a flash of Ben Willis is seen behind Amber, and then the film cuts to black as Amber's scream is cut off by the sling of the hook.
