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.

Five-0 is baffled when a highly skilled ring of thieves pulls off the heist of an armored car, killing two security guards but leaving the money behind. Their only lead in the case requires Danny to reluctantly ask his ex-wife for a favor.