What starts as a harmless online prank for Avery Lindstrom, Anne Winters, Mandy Kim Lauren Gaw, and Kaley Mack Annalisa Cochrane quickly spirals into something darker when they create a fake dating profile and begin to chat with John Bennett Travis Hammer, a lonely, socially awkward computer programmer. John’s long history of isolation and bullying fuels a growing desire for revenge once he discovers he was catfished. Through some online digging, he learns that the photo used for his supposed girlfriend actually belonged to a deceased Filipina model, and a post on their blog reveals the real identities of the three girls—the cruel prank laid bare for all to see. This shocking turn sets the stage for a calculated plan to strike back.
While Avery and Mandy feel remorse for their actions, Kaley Mack Annalisa Cochrane remains unrepentant, earning the label of the school’s “mean girl.” In a bid to torment the trio, John hires a good-looking young man named Nick to play along, telling him he’s staging a trick on his niece and wants the girls to fall for him, only to stand them up. Nick, described as a male escort, becomes an instrument in John’s scheme, with the plan hinging on the girls’ growing interest turning into a tangible connection.
John locates the Skatelab skate park, the girls’ hangout, and sends Nick there to flirt with them. The ruse works, as Kaley [Annalisa Cochrane] and Mandy give Nick their numbers. Nick explains he had just moved from Pittsburgh, and the girls invite him to Avery’s party. He doesn’t show, but he does send a text inviting Kaley and Mandy to Skatelab—an invitation that comes from John’s hand. When the girls arrive, it seems like no one is there, and danger quickly follows. John abducts Mandy outside, while Kaley initially suspects the incident is a prank from Avery or Mandy. Kaley returns to the party and ends up pulling a prank of her own on Avery’s crush, Trevor Lansing, by dousing his pants and posting the moment on their blog, intensifying Avery’s frustration and shattering their friendship.
Back at Kaley’s home, John uses his hacking skills to disable her home security, then enters and abducts Kaley, taking her to the warehouse where Mandy is being held. The next day, Avery sits for an interview with an agent as the missing-girls case draws in their worried parents. Avery warns the agent about Nick, and the police zero in on him as a potential suspect. Nick speaks with the cop and reveals John’s involvement, though he claims he didn’t know the full extent of the plan.
The situation escalates when Avery is kidnapped as well, and John brings all three girls to a warehouse with the intention of selling them to a man he found online. The would-be trafficker turns out to be a scam artist who only abducts Kaley, leaving Mandy and Avery at John’s mercy. John brings the two back to the warehouse, where Avery fights back, slashing him with a shard of glass in a desperate bid to escape. The neighbor, a hooker who lives next door, steps in and shoots John in the arm, enabling Mandy and Avery to flee. John retaliates by shooting the neighbor in the chest, then relentlessly pursues the trio, who hide in the warehouse armed with the neighbor’s gun and a cell phone to call for help. The police arrive to rescue them, and John, devastated by his actions, ends his own life before officers can arrest him.
In the hospital, Avery is questioned by law enforcement as she begins to process what happened. The final scene follows her as she clears Kaley’s locker, a somber note underscored by her voice-over explaining that Kaley Mack was never found, leaving a haunting question about the fate of one of the film’s central antagonists and the lasting impact of the cruel online prank.
