Rebecca's sudden arrival throws Joan into turmoil as she struggles with how to tell her daughter about the murder charges against Ian. Tracing Ian's last movements is put on hold when a neurodivergent Indigenous boy goes missing and the search becomes a potential abduction investigation. Rebecca is determined to bring her mother back to London and begins to question Joan's well-being.

When Jack is struck by a hit-and-run driver, it sparks some unexpected truths and the return of a threat from Jack's past. As Jack recovers, he and Joan track down Ian's long-lost son, who holds the keys to the mystery. But is she ready to put the past to rest? And will the new threat facing Jack see the end of this journey together?