Island Bound by Betty Levin

Chris Fossett can't resist a dare to spend a week alone on rocky, isolated Fowlers Island off the coast of Maine. He expects to spend his time hunting for food--not ghosts. But there's no denying an eerie presence in the fog, and Chris recalls his grandfather's tales of a girl who was left behind on the island. A fierce girl...who may still be there.

Joellen Roth, who comes to the island's bird cliffs with her scientist father and his new girlfriend, wants nothing to do with Chris--nor he with her. But when the two stumble upon a hidden journal, the pages reveal a story strikingly similar to one that Joellen is writing.