The Mystery of Carlos Madrid introduces the reader to Texas investigative reporter, Alejandro Cantu, who, while away on a much-needed beach vacation, is interrupted on his first day of leisure by a familiar picture in the local newspaper. The picture is a striking resemblance of Cantu, himself, but shockingly is located in the Obituary Section of the newspaper. This revelation sends chills all through Cantu since the man in the picture could be a twin brother he never knew existed. This immediately places the vacation on pause and sets Cantu onto a riveting investigation in an attempt to determine whether labor leader, Carlos Madrid, was his unknown twin, or simply a doppleganger with an uncanny resemblance. In the process of the investigation, Cantu meets sassy waitress and graduate student, Gina Silva, who seems to know everyone in deep South Texas and Madrid's widow, Jenny, who Cantu is drawn to in surprising ways.