Sophisticated sixteen-year-old New Yorker Julia is not expecting much excitement when she leaves the city to spend the summer as an au pair on Cape Cod. But when plans are made to remodel the dilapidated old house where she is staying, strange things begin to happen. Julia and her young charge, Molly, suspect the house is being haunted by the ghost of Molly's deceased mother, Maria. But after a frightening incident on the night of the blue moon, Julia and Molly realize they must stop chasing down the spirit of the mysterious Maria and live in the present.