In 1989, the city of Derry, Maine, was shrouded in the shadow of terror. Since the previous year, cases of missing children have occurred one after another, and it seems that a terrible unknown existence has quietly come to people. Billy (Jaeden Lieberher), a teenager who lost his brother, decided to use the summer vacation with Eddie, Ricky, Stanley and other partners to find the whereabouts of his brother George. Soon after, Ben, a fat boy bullied by the little villains, Beverly, a bad girl who was rumored to be debauched, and Mike, an orphan whose parents died in a fire, joined this sneered loser alliance. In the process, they experienced a series of supernatural horror experiences. The teenagers found that in this cursed city, the number of abnormal deaths would soar every 27 years. The grinning clown (Bill Skarsgård) went deep into everyone's heart and dug out the most feared part of them... This film is adapted from Stephen King's original work of the same name.