Felix and Carl suspect a Tug Master at the local harbour may be part of a drug-smuggling ring, but Carl's personal life threatens to collapse the operation. As Jo's final sergeant's exam looms, she must confront her life decisions while working on an internet dating scam, and Lino meets a potential love match - but Donna cannot stand her. Elsewhere, Jake witnesses a darker side to his mentor when Ryan loses his temper after revelations about his son.