Following the abduction of a former NSA cyberterrorism expert, the team must rescue the man and prevent a breach of national security.

When Danny's ex-partner is found dead at a Hawaiian luau the Five-0 team's investigation leads them to some dirty cops and a powerful cocaine cartel.

After a high-speed chase, the team makes a gruesome discovery; Chin Ho and his ex-fiancee are awkwardly reunited.

While Five-0 races to stop a mad bomber before he kills again, Danny gets an unexpected visit from his little brother, Matt, a fun-loving, Wall Street broker. The family reunion is cut short, however, when Danny discovers the real reason that Matt is in Hawaii.

When Five-0 gets too close to the truth about Wo Fat and his associates, the criminal mastermind retaliates by trying to destroy the team. They've always played by their own rules, but when the Governor can no longer protect them, it's time for Five-0 to pay the consequences of their actions.

While McGarrett sits in prison awaiting trial for the murder of the governor, Danny brings him a surprise visitor to help clear him. Meanwhile, Kono is suspended from the force, pending an internal investigation.

McGarrett finds himself in need of the Five-0’s help when he goes to North Korea with Jenna Kaye to deliver a ransom to rebels who are holding her fiancé hostage. Meanwhile, the Five-0 investigate the murder of an investigative reporter who seems to have ties to Jenna.

When the team almost causes an international incident, Lt. Gov. Denning decides that one of them should be fired; Chin Ho faces the harrowing task of choosing a Valentine's Day gift for Malia.

Five-0 is in hot pursuit of a shooter who guns down one of their own, while another team member is forced to choose which of their kidnapped loved ones will live.