Inspired by the bestselling novel of the same name by Hideo Yokoyama, 'Six Four' is a dark and compelling story of kidnap, corruption, betrayal and an uncompromising search for the truth. The series follows Chris (Kevin McKidd) and Michelle (Vinette Robinson) whose world is rocked when their daughter goes missing. Michelle takes her skills as a former undercover officer and tries to get to the bottom of the case, while Chris, a serving police detective, is simultaneously confronted with a similar case of a local girl's disappearance that has gone unsolved. Will they manage to get to the bottom of this case, that also involves politics and extortion?