Hawaii Five-0 Season 9 Episode 18 : Ai no i ka 'ape he mane'o no ko ka nuku (He Who Eats ‘Ape is Bound to Have His Mouth Itch)

Tani and Junior go undercover at a gym to track down a deadly batch of steroids that's killing users, before the drugs claim any more victims. Also, Danny and MacGarrett sub as bodyguards for Danny's high maintenance ex-mother-in-law, Amanda Savage, a wildly famous romance novelist with whom he has never gotten along.