The Night of the Moonbow - Thomas Tryon

Cabin 7 was supposed to be the lucky one at Camp Friend-Indeed, a Bible camp nestled in the piney woods next to Moonbow Lake in rural Connecticut. But it was 1938, a year notorious for cruelty, unnatural acts of terror. Cabin 7 was chosen to get the new camper - a mysterious orphan with a talent for music and more interest in collecting spiders than winning at baseball. The camp motto was "Glad men from happy boys," but the new camper would briing a chilliing secret to this final season...a season when the legendary moonbow would appear over the lake, when an orderly society of boys would transform itself into something primitive and dangerous...when the evil already loose in the world would be made flesh in one summer night of murder and madness.