Emily Young, a senior, wants to be elected as her sorority's president. She adopts a cute sloth, thinking it can become the new mascot and help her win, until a string of fatalities implicate the sloth as the main suspect in the murders.

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.