Ginny Donovan is a young woman with a lifelong fascination for pirates stemming from an old memoir she had found as a child in her grandparents attic. While away at college a mysterious illness has her grandmother near death. Rushing back to her home town in Pennsylvania, Ginny is given a key that has been in the family for many generations. Upon her death, her grandmother starts her on a quest to find what the key goes to and to find who she really is. Ginny receives help from an archaeologist, Mr. Thomas Mansfourth as they find themselves in the middle of a scavenger hunt that sends them on a trip to historical places along the eastern coast and across the Atlantic. Along the way, mysterious things begin happening. She and Mansfourth are followed by several people. Some want to help her, whereas others are willing to go to any length to try to stop her from finding the truth.