A letter written by a seriously ill middle aged man facing the end of his life is found in a safety deposit box after he passes away. The document, immediately thought to be Jack Quinn's last will and testament, sends his oldest friend on a quest to find his birth parents, his adoption only revealed to him shortly before he died. The search for the identity of the decedent's birth parents takes Mark Purchell, a man who has been Quinn's friend for over forty years, from his hometown of Ottawa to a small town on Cape Breton Island in Nova Scotia. Along the way, Purchell encounters and is assisted by a number of intriguing characters, including a seedy but well-meaning neighbour, a stern librarian, a retired police officer, members of the clergy, a newspaper editor, a haughty hotel maitre d' and a spirited waitress named Elaine. His investigation of The Hidden History of Jack Quinn eventually leads to a newspaper archive and a surprising answer to a departed friend's last request.