Freddy vs. Jason is a 2003 American slasher film directed by Ronny Yu and written by Damian Shannon and Mark Swift. It is a crossover between the Nightmare on Elm Street and Friday the 13th series, being the eighth installment in the former and the eleventh in the latter. The film retroactively establishes the two series in a shared universe and pits their respective antagonists, Freddy Krueger and Jason Voorhees, against each other after the former manipulates Jason into coming back to life and attacking the residents of Springwood to facilitate his own return. It is chronologically set after Freddy's Dead: The Final Nightmare (1991) and Jason Goes to Hell: The Final Friday (1993) but before Jason X (2001), and is the last film in each franchise before their respective reboots.
Freddy vs. Jason was released in the United States on August 15, 2003. It grossed over $116 million worldwide, making it the highest-grossing film in for both series. The film marks Robert Englund's final cinematic appearance as Freddy Krueger. A sequel and crossover with the Evil Dead franchise was planned, but it was ultimately scrapped and turned into a comic book limited series, Freddy vs. Jason vs. Ash.
Freddy Krueger, confined in Hell since his latest defeat and unable to invade dreams as the adults of Springwood have gone to extremes to make sure their children have forgotten about him, uses his remaining powers to resurrect Jason Voorhees, who is also trapped in Hell after his demise. Freddy appears to Jason in the form of his mother to manipulate him into killing the teens of Springwood to create fear, allowing Freddy to regain his strength as the adults will assume he has returned.
Meanwhile, Lori Campbell, who lives with her widowed father, has a sleepover with her friends Kia Waterson and Gibb Smith. They are later joined by Trey, Gibb's emotionally abusive boyfriend, and his friend Blake Mueller. Jason enters the house and murders Trey Cooper, and the police suspect Freddy. After a nightmare, Blake awakens to find his father killed by Jason, who then kills Blake himself. The police call it a murder–suicide the following day, hoping to conceal Freddy's return from the rest of the town.
Elsewhere, Lori's ex-boyfriend Will Rollins and his friend Mark Davis, forcibly institutionalized at the Westin Hills Psychiatric Hospital with others, are made to take Hypnocil to suppress their dreams because of their previous contact with Freddy. A news report about the killings prompts them to escape and return to Springwood to warn Lori about Freddy. That night, Lori and the others attend a rave in a cornfield. Freddy tries to kill Gibb in a nightmare, but Jason kills her first in the real world after attacking the rave, angering Freddy.
Will, Lori, and Kia escape the rave with school nerd Charlie Linderman and stoner Bill Freeburg. After dropping off the latter three and a confrontation with Dr. Campbell (who was responsible for having Will and Mark committed to Westin Hills) over Will's certainty that he saw Lori's father murder her mother, Will and Lori head to Mark’s house, only to see Mark get killed by Freddy. Deputy Scott Stubbs, believing Jason is a copycat, makes contact with Lori and her friends, who deduce Freddy's plan. Learning about Hypnocil, they try to steal it from Westin Hills; however Freddy possesses Freeburg, using him to dispose of the medicine. Jason then arrives and kills Stubbs, however Freddy uses the possessed Freeburg to tranquilize Jason, causing him to fall asleep after killing Freeburg.
The teens devise a plan to pull Freddy from the dream world into reality and force him to fight Jason, bringing the unconscious Jason to the now-abandoned Camp Crystal Lake. Freddy fights Jason in the dream world, where he discovers that Jason has a subconscious fear of drowning (symbolized by the water released from a broken pipe) as a result of his drowning back in 1957. Using this to his advantage, he uses water to make Jason powerless; however, Lori goes to sleep in order to pull Freddy out and save Jason. As Freddy tortures Lori in the dream world, revealing that he murdered her mother, Jason awakens at the real Camp Crystal Lake and pursues the teens, killing Linderman. Lori is awakened and pulls Freddy into the real world, (showing briefly a fear of fire, as a result of his death by burning) where he is confronted by Jason.
Freddy and Jason fight throughout the campgrounds, during which Jason kills Kia. Freddy uses the construction site to his advantage and cuts off Jason's fingers, allowing Freddy to take his machete. As Freddy is slicing away at Jason, Lori distracts him before Jason punches his fingerless hand through Freddy's torso. Freddy retaliates by plunging Jason's machete into his side and Jason rips Freddy's gloved arm off. Lori and Will set the dock on fire, causing propane tanks to explode and throwing Freddy and Jason into the lake. Freddy climbs out and tries to kill Lori and Will with Jason's machete, but he is impaled by a wounded Jason with his own clawed arm, allowing Lori to decapitate Freddy with the machete. Jason and Freddy's headless body sink into the lake, both seemingly dead. After throwing the machete into the lake, Lori and Will leave the scene.
The following morning, a victorious Jason emerges from the water, holding his machete and Freddy's severed head. Freddy's head suddenly winks at the camera as his laughter is heard in the background, implying that he is still alive.