It

This is an adaptation of the 1986 novel by Stephen King.  Set in 1989 (as opposed to the novel's 1958 setting) in the small town of Derry, Maine, which has been terrorised by a spate of mysterious disappearances of children.  Seven young outcasts, who call themselves "The Loser's Club" decide to put a stop to it:  Bill Denbrough (Jaeden Lieberher) has a bad stutter and his younger brother, Georgie, is among the missing; Ben Hanscom (Jeremy Ray Taylor) is picked on because he is overweight; Beverley Marsh (Sophia Lillis) is abused by her father and is the subject of cruel rumours; Richie Tozier (Finn Wolfhard) is the group clown, often getting in trouble due to his loud mouth and foul language; Stan Uris (Wyatt Oleff) is picked on because he is Jewish; Mike Hanlon (Chosen Jacobs) is subjected to racist bullying; and Eddie Kaspbrak (Jack Dylan Grazer) has become a hypochondriac due to his over-protective mother.  They discover that the culprit is Pennywise the Dancing Clown (Bill Skarsgard), who is in reality an evil, shapeshifting entity which feeds on fear, particularly children's fear. 

Previously adapted as a two part TV miniseries in 1990 which was re-edited into a feature film; It is one of Stephen King's best known books.  The film lacks the richness of the book, but is an effective horror film, with a reliance on sudden jump scares.  It is well acted, and the film really shines in  the quieter character moments.