Childhood sweethearts re-unite as adults and find love again. After a failed marriage, she was back together with the man she'd loved since high school. Until the morning of a fateful Friday the 13th, when a single shot rang out in a parking garage. It would take a different kind of luck for investigators to solve the mystery. NBC's Josh Mankiewicz reveals the answer to the Friday the 13th Mystery.at 9 p.m. ET, 8 p.m. CT.