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

While the team investigates the murder of a young computer hacker, McGarrett tries to stage a long-needed reunion between his mother and his sister.

After McGarrett and Wo Fat narrowly escape from maximum security, gunmen storm Five-0 headquarters, compromising Kono and Adam's secret location in Hong Kong and forcing McGarrett to break the law and turn on his own in order to find a kidnapped Catherine.

Five-0 tries to save a kidnapped college student from a dangerous vigilante. Meanwhile, Max, Kamekona and Flippa fight to survive after being shipwrecked.