The identity of the Zodiac Killer has remained a deep well of questions, theories and obsession for five decades. But, now, for the first time, a family has come forward to tell their story, reveal their never-before-seen evidence, and present their experience of a man who detectives working the case agree is the only suspect they've ever named. But even law enforcement has never seen what the Seawater kids, now adults, are about to share.