It
Stephen King

It is the children who see - and feel - what makes the small town of Derry so horribly different. In the storm drains, in the sewers, IT lurks, taking on the shape of every nightmare, each one's deepest dread. Sometimes IT reaches up, seizing, tearing, killing... Time passes and the children grow up, move away and forget. Until they are called back, once more to confront IT as it stirs and coils in the sullen depths of their memories, reaching up again to make their past nightmares a terrible present reality.