In the summer of 1989, a group of bullied kids band together to destroy a shape-shifting monster, which disguises itself as a clown and preys on the children of Derry, their small Maine town.

After a young couple take in their two nieces, they suspect that a supernatural spirit named Mama has latched onto their family.

Barry Allen uses his super speed to change the past, but his attempt to save his family creates a world without super heroes, forcing him to race for his life in order to save the future.

Twenty-seven years after their first encounter with the terrifying Pennywise, the Losers Club have grown up and moved away, until a devastating phone call brings them back.