(Warning! Spoiler Alert! Do not read if you haven't seen the movie yet, if you do not want to see the movie then go ahead and read, the story is the same! You have been warned!)
In Derry, an unknown comes every 27 years to kidnap little children and terrorise them with their fears. Poor little Georgie was dragged by the evil entity down into the sewers, which motivates Billy, his older brother, and the other members of The Losers Club to go ahead and haunt down the clown.
(The story is the same I just added a character)