When the CEO of a hugely successful surf company is murdered, Kono revisits her past while Five-0 is thrown headlong into the varied but interconnected worlds of North Shore surfing.

Hawaiian luau turns into a nightmare when the body of a dead cop, who turns out to be Danny's ex-partner from the Honolulu P.D., is found in the barbeque pit. Five-0's dogged investigation into the murder matches them against Internal Affairs, dirty cops and Hawaii's most powerful cocaine cartel.