A rather hapless dude buys a backpack at a garage sale. When people around him turn up dead, he comes to believe his new accessory may be to blame. Tracking its history, he discovers it has connections back to a haunted house in a small town called Amityville...

When a group of old college friends reunite at a remote lakeside cabin, they quickly realize something is wrong—the forest is too quiet, and the local wildlife is missing. Soon, they're hunted by a swarm of mutated, flesh-eating otters infected by toxic waste from a nearby chemical spill. As the blood-soaked chaos unfolds, friendships fracture and survival instincts kick in. With no way to call for help, the group must fight back using whatever weapons they can find—including a chainsaw and a whole lot of rage. But just when they think it's over, the infection reveals it may have already claimed one of their own.

Archibald the Amazing, a ventriloquist nearing the end of his career, gives one final performance with his dummy, Chucklehead. After the show, he tragically takes his own life in his hotel room-but his negative energy inhabits Chucklehead, transforming the dummy into a murderous force of terror. From a class reunion to hotel staff to unsuspecting bystanders, Chucklehead embarks on a blood-soaked rampage, vowing to make it a night to remember.