Seventh-grader Maddy Hale has faced enough challenges with numerous school changes and meeting new schoolmates without having to babysit her pesky, three-year-old brother. When her parents accept positions helping Miss Sarah, a former professional actress who now owns a boarding house in a quaint, seaside town in Maine, Maddy's whole world changes. With the help of the quirky boarding house residents, her courage blossoms, and she embarks on a number of mystery-solving adventures. The first involves locating Miss Sarah's prized necklace which disappeared under strange circumstances. The evidence points toward a friend, but Maddy isn't convinced. It's imperative that Miss Sarah wear her necklace for her birthday celebration. Can Maddy find the real culprit and return the necklace before time runs out?