Freddy Krueger finds himself trapped in Hell, simmering with rage as the parents of Springwood have broken free from their psychotic grips and learned how to prevent their children from remembering him, thus stripping him of his power to escape. In a desperate bid for revenge, Freddy seeks out Jason, luring him into his twisted plan by adopting the guise of Jason's mother, Pamela Voorhees. He convinces Jason to rise again and wreak havoc in Springwood, ensuring that while Jason conducts the slaughter, Freddy will reap the benefits of being feared once more.
Upon Jason's arrival in Elm Street, he sneaks into the house once owned by Nancy Thompson and Jesse Walsh, now the home of the young woman, Lori Campbell, and her widowed father. During a party at the house with Lori's friends—Kia, Gibb, Blake, and Trey—things take a horrifying turn when Trey becomes the first victim of Jason's merciless machete, subsequently bent in half in a gruesome display. The surviving friends are soon embroiled in a nightmare of police questioning, and tension heightens when Lori, after eavesdropping on some officers' conversation about Freddy, falls asleep—allowing Freddy to regain some of his lost powers.
Freddy attempts to attack Blake, but fails to inflict harm, opting instead to let Jason continue his bloodbath. Blake awakens to find his father horrifically beheaded, an act immediately followed by his own demise at the hands of Jason. The police, quick to deflect suspicion away from Freddy, declare Blake as his own killer, intensifying the chaos in Springwood. Amidst Lori's recurring dreams of Freddy, she reconnects with her boyfriend, Will Rollins, and his friend Mark, both of whom escaped from an asylum after learning about the murders that are terrorizing the town.
Things escalate during a rave party where Gibb, in a vulnerable dream state, encounters Freddy who has taken the form of the deceased Trey to lure her to her doom. Just as it seems all hope is lost, Jason intervenes, killing both her attacker and Gibb's attempted assailant. As the body count rises, Will, Lori, Kia, and others realize they need a strategy. Their plan? Return Jason to Camp Crystal Lake, enticing Freddy into the real world for a showdown, where he would find himself at a disadvantage. However, Freddy refuses to let his grip on their reality go easily; he dispatches Mark with a shocking farewell and uses Freeburg to keep the group from taking Hypnocil, the drug that would force them into wakefulness.
Trapped in Freddy's dream world, Jason discovers he has been deceived. Initially, Freddy believes Jason fears nothing, but soon he identifies Jason's deep-rooted fear of water and uses it against him, drawing him into a haunting childhood recollection where Jason finds himself drowning. Just when Freddy is poised to deliver the final blow, Lori's intervention disrupts the battle, waking Jason who then turns his rage toward the group at Crystal Lake.
With revenge in his sight, Freddy reveals the horrific truth: he was responsible for the death of Lori's mother. But Lori, now driven by defiance, pulls Freddy into a conflagration within a cabin. As Jason witnesses the burning chaos, he grapples with Freddy, leading to an explosive confrontation where they go head-to-head. Lori, along with Will and Kia, strives to escape the chaos, but tragedy unfolds, leading to numerous losses within their group. Ultimately, Lori realizes she must confront Freddy directly, leading to a cascade of explosive events caused by igniting gasoline tanks in a desperate attempt to eliminate both threats.
The battle results in devastating injuries for both Jason and Freddy. In a final display of strength amidst the flames, Jason rips Freddy’s arm free, while Freddy plunges his claws deep into Jason's heart. The conflict culminates in an explosive finale, casting both figures into the depths of Crystal Lake. As the waters settle, Freddy makes one last attempt on Lori's life wielding Jason's machete, but Jason rises once again. In a final act of defiance, he stabs Freddy with his own claws, as Lori claims Jason's weapon, uttering the chilling phrase: > "Welcome to my world, bitch!" before decapitating Freddy.
As the dust settles, Lori and Will manage to escape, but the next morning unveils a shocking twist: Jason resurfaces from the lake, clutching his machete and Freddy's severed head, which smirks and winks at the audience, leaving everyone questioning who the real victor in this prolonged battle of nightmares truly is.
