Synopsis for
Friday the 13th (1980)

In a brief prologue set in 1958, two summer camp counselors at Camp Crystal Lake sneak away from a camp fire sing-along to have sex. Before they can completely undress, an unseen assailant sneaks into the room and murders them both. The film moves forward to 1980; a young woman named Annie (Robbi Morgan) enters a small diner and asks for directions to Camp Crystal Lake, much to the shock of the restaurant's patrons and staff. A strange old man named Ralph (Walt Gorney) reacts to the news of the camp's reopening by warning Annie that they are "all doomed". Enos (Rex Everhart), a truck driver from the diner, agrees to give Annie a lift halfway to the camp. During the drive, he warns her about the camp, informing her that a young boy drowned in Crystal Lake in 1957, one year before the double murders occurred. After Enos lets her out, Annie hitches another ride in a jeep. The second driver, whose face is never seen, ends up murdering Annie by slashing her throat with a large hunting knife.At the camp, the other counselors, Ned (Mark Nelson), Jack (Kevin Bacon), Bill (Harry Crosby), Marcie (Jeannine Taylor), Alice (Adrienne King), and Brenda (Laurie Bartram) are refurbishing the cabins and facilities along with the camp's owner, Steve Christy (Peter Brouwer). As a violent storm closes in on the horizon, Steve leaves the campgrounds to get more supplies. The unidentified killer begins to isolate and murder the counselors. Later that evening, Steve returns from town and is also murdered, apparently familiar with his attacker. Alice informs Bill that she saw the lights turn on at the archery range and that she thinks she heard Brenda screaming. Bill and Alice leave the cabin to investigate, and find a bloody axe in Brenda's bed. Attempting to phone the police, they discover the phones are dead and that the cars won't start when they try to leave. When the lights go out all over the camp, Bill goes to check on the power generator. Alice heads out looking for Bill; when he doesn't return, she finds his body pinned to a door by several arrows. Now alone, Alice flees back to the main cabin and hides. After a few moments of silence, Brenda's corpse is hurled through the window. Alice hears a vehicle outside the cabin and, thinking it to be Steve, runs out to warn him. Instead she finds a middle-aged woman who introduces herself as Mrs. Voorhees (Betsy Palmer), an "old friend of the Christys". Alice hysterically tries to tell her about the murders. Mrs. Voorhees expresses horror at the sight of Brenda's body, but she soon reveals herself to be the mother of the boy who drowned in the lake in 1957. Talking mostly to herself, she blames her son Jason's drowning on the fact that two counselors were having sex and were unaware of Jason's struggling in the lake. Mrs. Voorhees suddenly turns violent and pulls out a large knife, rushing at Alice. A lengthy chase ensues, during which Alice flees her attacker and finds Steve and Annie's bodies in the process. Alice and Mrs. Voorhees have several confrontations, each time with Alice believing she has finally beaten Mrs. Voorhees. During their final fight, Alice manages to decapitate the defenseless Mrs. Voorhees with her own machete.Afterwards, the decomposing "corpse" of Pamela's son, Jason (Ari Lehman), attacks Alice while she waits for help in a canoe. Just as she is dragged under water, she wakes in a hospital, where a police officer tells her that they pulled her out of the water. When she asks about Jason, the officer informs her they never found any boy.