When fourteen-year-old Anna Shipherd receives mysterious messages, she knows they are from her twin brother, Toby, who left two weeks earlier aboard an oyster dredge boat. The messages are only the beginning. A strange letter written in a foreign language arrives for her in the mail, and soon Anna realizes that someone is following her. An exciting blend of mystery and history, Oyster Moon is set on Maryland's Eastern Shore in the late 1800s, at the peak of the tumultuous Oyster Wars.