While playing a mystery game at a stately island mansion, Matlock discovers the 'victim' in the game has been murdered in real life. In the matter of one evening, the island hideaway goes from perfect vacation spot to crime scene and Ben is on the case.

When Matlock helps a down-on-his-luck PI find his long-lost daughter, the father and daughter team end up working together to solve the toughest murder case of the father's career, while building a relationship that changes their lives forever.