The island of O'ahu goes on lockdown when Five-0 hunts a terrorist who starts using weaponized drones on civilians. Meanwhile, McGarrett and Danno must go for a mandated review with a psychologist, resulting in a session which looks a lot like couples therapy.
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. Chi McBride guest stars as SWAT Captain Lou Grover and Henry Ian Cusick guest stars as a member of a terrorist organization.
When a Detroit hit man is taken out by one of his colleagues on the streets of Oahu, Five-0 is shocked to learn the killer's surprising motives. Meanwhile, Chin puts his career on the line to help Danny get the money he needs to save his brother's life.
It's an All-Pro football weekend in Hawaii and while Danny obsesses about the big game, Five-0 investigates the murder of a tech executive with the help of a star football player. Arian Foster, Pat Monahan, and Larry Manetti guest star.
It's Christmas in Hawaii and Five-0 travels to the Big Island, where Max is forced to work with a rival medical examiner after a cowboy is poisoned. Meanwhile, McGarrett pressures Danny into stealing a Christmas tree.
