As a dangerous hurricane hits Oahu, Five-0 is tasked with protecting El Diablo, a captured serial killer who is being hunted by an assassin. Also, Tani's civilian safety check during the storm turns deadly and Rachel and Charlie evacuate to Danny's house, where the ex-spouses reminisce.

Junior is torn between his duties as a member of Five-0 and his feelings for his former girlfriend when her new love, the father of her son, is one of the culprits in a bank-heist-turned-homicide.