One year after the tragic death of their beloved friend, a group of college friends reunite for a memorial weekend in the mountains. Led by Cameron, his protective friend Kelsea, and their circle of peers, the group arrives at a secluded lakeside cabin hoping to find closure and celebrate the life of the friend they lost. Tensions quickly surface around the evening campfire. Old romantic jealousies, buried secrets, and unspoken guilt regarding the night their friend died begin to fracture the group's unity. Unknown to the friends, a masked figure watches them from the tree line, armed with woodland tools and driven by a thirst for retribution. As darkness settles, the terror begins. When one of the boys wanders out to check the generator, he is ambushed and brutally impaled. Panic erupts when the remaining friends discover the severed phone lines and slashed vehicle tires. Trapped miles from town with no cellular reception, the friends barricade themselves inside the cabin, unaware that the killer has already slipped indoors. One by one, the group is hunted down in a series of tense cat-and-mouse skirmishes. Cameron steps up to defend his remaining friends, using his wits and courage to outmaneuver the stalker. Suspicion runs wild as the survivors begin accusing one another of being the mastermind behind the bloodshed. In a frantic final confrontation through the shadowy woods and shoreline, the killer is unmasked, exposing a shocking connection to their dead friend's final hours. Battered, bloodied, but refusing to back down, Cameron fights back in a desperate battle for survival, proving that boys can be final survivors too.

The climax of The Final Boy delivers a classic slasher reveal with an emotional sting. The killer is revealed to be driven by twisted vengeance, holding the entire group responsible for the accidental drowning of their friend during a reckless party the previous year. The killer believed the group covered up their negligence and deserved to pay with their lives. In the brutal final showdown on the docks, Cameron is pushed to his absolute limits. Rather than waiting for a rescuer or running in blind panic, Cameron uses the killer's overconfidence against them, turning their own weapon around in a fierce struggle before pushing them into the dark waters below. As morning light breaks over the misty lake, local authorities and Sheriff Wilkins arrive at the scene. Cameron sits wrapped in a shock blanket on the back of an ambulance, injured but alive. He looks out over the tranquil mountains, having survived the night through sheer resilience and honoring his friends' memories by refusing to be another victim.