White Room by Rick Hautala

Trade paperback format. 

Heading for Hilton, Maine, to spend the summer restoring his old childhood home, Tim and Polly Harris and their young son, Brian, encounter more than they had bargained for when human bones are found at a nearby construction site, Brian nearly drowns, and Polly encounters a mysterious young girl whom no one else can see and an evil force bent on their destruction.

"Rick Hautala’s writing shines with dedication, hard-earned craft, and devotion." - Peter Straub