Blood Brothers ~ Nora Roberts

This is the first in the Sign of Seven trilogy. Cal Hawkins and his two best friends went out on a camping trip for their tenth birthday, and inadvertently set something free. What ever it is comes back every 7 years, for 7 nights. Now, as the 3rd return approaches, Quinn wants to write a book about the strange happenings in Hawkins Hollow. She gets to town and starts to investigate, and strange things begin to happen. Will they figure out what they need to do?