In a haunting prologue set in 1958, two summer camp counselors at Camp Crystal Lake, Barry and Claudette, sneak away from a campfire sing-along for an intimate rendezvous. However, their romantic interlude is abruptly cut short as an unseen assailant enters the room and tragically murders them both.
Fast forward to Friday, June 13th, when a young woman named Annie arrives at a small diner, seeking directions to the infamous Camp Crystal Lake. Her inquiry shocks the locals, including a bizarre old man named Ralph, who eerily warns her that they are "all doomed." A friendly truck driver named Enos offers to drive her halfway to the camp, cautioning her about a tragic incident involving a young boy who drowned in the lake back in 1957, just before the grisly murders occurred. After being dropped off, Annie hitches a ride with an unknown driver in a Jeep. When the driver neglects to stop where she wishes, Annie leaps from the moving vehicle, only to find herself hunted in the woods, ultimately meeting a brutal end as her throat is slashed with a bowie knife.
At the camp, other counselors—Ned, Jack, Bill, Marcie, Alice, and Brenda—are busy refurbishing the facilities under the watchful eye of their demanding boss, Steve Christy. They soon experience eerie occurrences, including a prank where one counselor pretends to drown and a deeply unsettling visit from Ralph, who repeats his doomsday warning. As a storm looms, Steve heads out to pick up supplies, leaving the group to fend for themselves.
Unbeknownst to them, a mysterious killer clad in a hooded black rain slicker begins to stalk the camp, picking them off one by one. After witnessing the killer in action, Ned follows the figure into a cabin, leading to his inevitable doom. As the storm rages on, Marcie and Jack engage in their own private pursuit of romance, oblivious to the lifeless body of Ned above them. Their blissful encounter is shattered when Jack falls victim to the killer’s arrow, violently striking his throat from below.
Marcie, hearing strange noises while in the bathroom, naively investigates, only to meet a gruesome end at the hands of the assailant wielding a deadly axe. Later, Brenda, drawn outside by a child-like voice, is lured away only to vanish into the rain, her fate sealed at the hands of the lurking menace. When Bill and Alice find remnants of the violence in the form of a bloody axe, they grow increasingly suspicious as communication lines are cut and vehicles refuse to start.
Meanwhile, Steve faces his own uphill battle after getting stuck in the mud on his drive back, ultimately requiring a ride from a passing officer. As Steve makes his way back to the camp, he unexpectedly falls victim to the very hand that once protected him.
As darkness falls and power flickers, Bill heads to check the generator, while Alice discovers his arrow-pierced corpse. In sheer panic, Alice hides as Brenda's lifeless body is hurled through a window. A search outside leads to a shocking encounter with Mrs. Voorhees (played by Betsy Palmer), who deceives Alice with a facade of friendship but soon reveals her true nature fueled by a vendetta over her son Jason’s tragic fate.
> "You see, he was not dead. He was waiting for me to come back." Mrs. Voorhees viciously explains her motive; anger at the counselors for their negligence while her son drowned. Caught in a deadly showdown, Alice musters her strength and manages to push back against Mrs. Voorhees with anything she can find.
The two engage in a fierce battle, racing through the camp grounds until Alice finally gains the upper hand, leading to a heart-stopping climax by the lake, where she decapitates her assailant, momentarily believing the horror to be over.
Shocked and traumatized, Alice drifts out onto the lake in a canoe, seeking peace but not yet escaping the grasp of terror. The morning after, as she is rescued, the calm lake reveals the true horror—the decomposing body of Jason emerges, pulling her into the depths just before she awakens in a hospital, where the grim reality dawns on her. The officer reveals the chilling fact that no boy was found, prompting Alice to declare, "Then he's still there," a haunting reminder that the darkness of Camp Crystal Lake may never truly rest.
