Michael Hobart Sullivan's "Grandpa Sully" wasn't born a Sullivan. Michael didn't discover that till 35 years after his grandfather's death.

After Michael's father dies, he begins sorting through what remains and finds an old harmonica, a damaged cassette tape, a photograph, and a box of papers that point toward a family history no one ever fully explained. One of the papers is a signed "Indenture" contract between the New York Foundling Hospital and the Sullivans in rural Arkansas. The child named in it is Hobart Adams.

Michael has questions. Who was Hobart Adams? Who were his biological parents? When did Grandpa Sully learn the truth about his own beginnings? When did Michael's father know? And why wasn't Michael told?

Michael begins a search through genealogy, old records, family stories, and the history of the Orphan Trains. Each answer uncovers another fragment, and some of the stories Michael thought he understood begin to change.

"The Harmonica Box" is an author-narrated, family-mystery memoir about ancestry, an Orphan Train child given a new identity, and a grandson trying to uncover what was hidden. What begins as a search for the truth about Grandpa Sully becomes something larger: a story of lineage, fathers and sons, and what can happen when someone finally starts opening the boxes.