After Mark agrees to be a cruise ship doctor as a favor to a friend, he invites Steve, Jesse, and Amanda along for the trip. Upon arriving on the ship, it doesn’t take long before the doctors get their first patient: saving the life of a multimillionaire passenger who had an overdose of insulin; and who is later drugged and thrown overboard by his wife. When his body is later recovered, his daughter is accused of his death by his widow. As Mark and the others investigate, they soon discover that the widow’s first husband also died of suspicious circumstances on a different cruise and it had something to do with his life insurance policy.