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.
When evidence to put away a drug kingpin is stolen, Lucy goes undercover at an underground poker tournament to find out which high-roller is behind the crime. Also, Lucy's feelings are in turmoil when Whistler's ex-girlfriend arrives in town.
When threats turn deadly against a tour company that endangers the local shark population, Five-0 faces the difficult task of narrowing down the suspect list. Meanwhile, the team debates whether or not Kamekona will earn his helicopter license.