Seven friends in Derry, Maine are haunted by a clown named Pennywise, who they believe is real. When the leader of the group's brother falls victim to the evil, they set out to stop it.

Thirty years later, the Losers Club reunites as adults when Mike suspects Pennywise has returned. They uncover new powers, clues, and evil as they face the force that has plagued Derry for centuries.