Episode 4 (S01E04)

While Jack and Joan get ready to celebrate her first Christmas in the southern hemisphere by the ocean, a reef diving trip takes a disastrous turn. Joan springs into action to help an injured diver, as a young woman's survival hangs in the balance. In their quest for answers, Joan and Jack uncover that the incident is actually a deliberate act of sabotage. This revelation strikes a personal chord for Jack, prompting him to track down a woman from his past to rectify his previous errors.