Claudia and the Lighthouse Ghost

When the Hatts, old family friends of the Kishis, come to stay at Claudia's house, things get pretty cramped and tempers flare. The Hatts own the old Stoneybrook lighthouse, which has lately been the site of some spooky occurences. Someone - or something - wants the Hatts to leave town...or else. Gradually, a tragic story emerges - a tale involving a death, the lighthouse, and the Hatts. The Baby-sitters suspect that someone tied to this dark event is behind the new troubles. But can they figure out who, and why, before somebody gets hurt?