The film begins with a sequence of television reports indicating that the Collector has escalated to a serial killer, attracting a vast police manhunt. Much like the previous installment, the Collector eliminates all of his victims, except for one whom he kidnaps. Arkin, played by Josh Stewart, is the most recent of these unfortunate souls. In this tense atmosphere, Elena Peters (portrayed by Emma Fitzpatrick) is taken by her friends to a clandestine party at a secret location.
At this gathering, Elena is devastated to see her boyfriend, who abandoned their date, in the company of another woman. Reacting to her anger, she breaks his nose and storms off the busy dance floor into a secluded room. There, she stumbles upon a disturbing sight: a red trunk containing a badly injured Arkin. In a desperate moment, Arkin seizes her and they narrowly evade a steel spear that shoots from the wall, triggering a series of deadly traps. The horror escalates as a massive rotating mechanism with blades wreaks havoc on the dance floor, mercilessly shredding numerous party-goers. Stricken with terror, Elena flees the room only to activate a trip wire, leading to thin swords that shoot out from the walls, inflicting lethal injuries on unsuspecting victims. As the situation worsens, the Collector looms above, executing his abhorrent methods as the ceiling lowers upon her friends, including Missy, slowly crushing them to death before an immobilized Elena.
In the ensuing chaos, the Collector seizes Elena, while Arkin makes a harrowing escape by using a body as a shield and leap out of a high window, landing painfully on a car and shattering his arm. Once at the hospital, Arkin is restrained by the police, who are keen to surveil him due to his criminal past. There, he encounters Lucello, the trusted aide of Elena's affluent father, played by Christopher McDonald. Lucello has assembled a team of mercenaries to track down the Collector and rescue Elena from his clutches. In exchange for leading them to the Collector, he offers Arkin a chance at redemption from his criminal history.
During his prior captivity, Arkin smartly marked the route to the Collector’s hideout with cuts on his arm, guiding the mercenary team to an abandoned hotel situated in a forgotten area of the city. However, when Arkin hesitates to enter, Lucello resorts to a betrayal, forcing him at gunpoint to navigate the perilous interior. Meanwhile, Elena cleverly uses her bra to create an escape route from the trunk, narrowly avoiding detection from the Collector, who deploys spiders to hunt her down as alarms blare in the background.
Upon their entrance into the hotel, the mercenaries confront demented foes with half-masks adhered to their faces, revealing the Collector's twisted experiments. Arkin seizes the chance to flee from Lucello’s controlling grasp. As the story unfolds, it intertwines the journeys of Elena seeking an escape, Arkin desperately trying to break free, and Lucello's team in pursuit of Elena. They each encounter grotesque human experiments and mutilated body parts rearranged in horrifying manners, heightening the sense of dread.
Trapped and terrified, Elena discovers a disheveled prisoner named Abby, who claims to be the Collector’s favored victim but is rigidly apprehensive about disobeying. In a moment of panic, Abby insists that Elena isn’t strong enough to escape the Collector’s grip. But when the Collector finds them, chaos reigns. Eventually, Elena, Lucello, and Arkin reunite to save another trapped victim, Paz, but their numbers dwindle as they confront twist after twist.
A plan to escape through a window proves futile as their cries for help go unheard by two homeless men outside. In desperation, Arkin fires shots to attract attention but inadvertently reveals their position, leading to betrayal when Abby turns on them. As the Collector retaliates violently, Lucello sacrifices himself during a final showdown, urging the group to save Elena while he faces the wrath of the Collector.
In a climactic struggle, Arkin and Elena discover her restrained on an autopsy table, triggering a perilous cage trap. The Collector, intent on destruction, unleashes fire upon the building, but Arkin's quick thinking allowed them to escape—only to discover the Collector's burned mask still hauntingly intact. In a bid for vengeance, Arkin hunts down the Collector, vowing to reciprocate the torment he endured, leading to a final confrontation in the Collector's house. As they clash, Arkin seals the Collector within the confines of a red trunk, determined to exact his retribution on the monster who tormented him.
