When evidence to put away a drug kingpin is stolen, Lucy goes under cover at an underground poker tournament to find out which high-roller is behind the crime; Lucy's feelings are in turmoil when Whistler's ex-girlfriend arrives in town.
When the CEO of a surf company is found murdered, Kono revisits her past and Five-0 is thrown headlong into the interconnected worlds of North Shore surfing.
The team investigate a string of arson attacks against a tour company, while Kamekona hopes to secure his pilot's licence.