In 1990, a little girl named Laurie Anne Winterbarger, returning home on her bike, is told by her mother to go inside since there’s a storm coming. As her mom goes inside, Laurie finds a dropped doll, and hears children and a man laughing. She spots a middle-aged man dressed as a clown, who attracts, and suddenly attacks her. Later, her mother goes outside, and screams in shock as she sees her daughter’s dead body. As the ambulance is transporting the dead girl, town librarian and private investigator Mike Hanlon finds a photo of a young boy named Georgie Denbrough, and he says “The killer’s back.” In Derry, Maine, in 1960, a young boy named George “Georgie” Denbrough is lured to a storm drain by the man in the clown costume who reveals his name to be Pennywise. Pennywise soon reveals his malevolent nature and rips Georgie’s arm off, killing him. Georgie’s older brother Bill and six other outcast children, who form a group called the Losers Club, discover they are all being tormented by the same mysterious clown. The group consists of the overweight and nerdy Ben Hanscom, asthmatic Eddie Kaspbrak who lives with his overbearing mother, Beverly Marsh who lives with her abusive father, comical Richie Tozier, Jewish Boy Scout Stanley Uris, and African-American outcast Mike Hanlon. In turn, all of them are tormented by a gang of local bullies led by Henry Bowers. The Losers theorize that Pennywise is not a deranged man in costume, but is an alien creature that surfaces every 27 years in Derry to murder children. They dub him “It.” To avenge Georgie and others killed by It, the Losers venture into the sewers where the clown lurks. They are followed by Henry and his friends Victor Criss and Belch Huggins, who threaten Stan, only for It to kill Victor and Belch, but spares the terrified Henry, whose hair turns white. It catches up to the Losers and grabs Stan, bragging that he is immortal and eats children. Guessing It’s powers are based on imagination, the Losers fight back using the same power, melting Pennywise’s face with imaginary battery acid and Beverly smashes a hole in his head using a silver projectile. Pennywise escapes wounded and the seven make a promise to return and kill him should It resurface. Henry is arrested and institutionalized when he falsely confesses to murdering his friends and the other children killed by It. In 1990, Mike summons his six friends back to Derry to fulfil their vow. Bill has become a horror novelist married to actress Audra Phillips, Ben is an architect, Beverly is a fashion designer in an abusive relationship with Tom Rogan, Richie is a late night TV comedian, Eddie runs a limousine service but still lives with his mother, and Stan is a real estate broker. While five of them agree to come, Stan commits suicide in his bath tub and writes “It” on the wall in blood. The remaining six are individually harassed by Pennywise before reuniting for dinner, though Pennywise frightens them there too. They learn of Stan’s suicide shortly after. Elsewhere, an older Henry is visited by Pennywise who sends him to Derry to kill the Losers. Audra also arrives in town but falls victim to It’s paralyzing “deadlights” and falls into a catatonic state. Henry wounds Mike, but is killed by his own knife during a scuffle with the other Losers. With Mike hospitalized, the five remaining Losers decide to destroy It for good. They descend into the sewers once again, encountering It in the form of Georgie. Bill overcomes the illusion. The Losers confront It in its lair, who now appears as a giant spider. Eddie is killed by It, but Beverly mortally wounds It with her slingshot, and the Losers tear the spider apart. They remove the comatose Audra and Eddie’s body from the sewers, burying him in Derry’s cemetery. The Losers go their separate ways, free from It’s torment forever. Richie is cast in a film, Beverly and Ben get married and are expecting their first child and Mike recovers. Bill manages to coax Audra out of her catatonia by going on a ride on his childhood bicycle, which had once freed a young Stan from his fear. With It gone, the Losers can move on with their lives and leave Derry behind. As the credits’ roll, Pennywise’s haunting laughter can be heard.