When former United States Navy officer, Steve McGarrett, returns home to Oahu to find his father's killer, the Governor offers him the chance to run his own special task force: Five-0.

Steve McGarrett (Alex O'Loughlin) comes to Hawaii to avenge his father's death, but when the Governor offers his own task force (the Hawaii Five-0), he accepts. He picks up team members on the way: Danny Williams (Scott Caan), the head detective on his father's case; Chin Ho Kelly (Daniel Dae Kim), a former Honolulu Police Department Detective who was fired for accused corruption and McGarrett's father's old patrol partner; Kono Kalakaua (Grace Park), a Cadet at the Police Academy who's one week from graduating; Lori Weston (Lauren German), entry to Five-O temporarily; Catharine Rollins (Michelle Borth), a girlfriend of Steve; and Captain Lou Grover (Chi McBride), a former Chicago Police Department Head of S.W.A.T.—ahmetkozan

Hawaii doesn't have its own state police force, but the Governor has set up a special task force, which becomes known as "Five-0", to investigate serious crimes on the islands. Reserve Naval officer Steve McGarrett (Alex O'Loughlin) heads the team with Danny Williams (Scott Caan) as his second-in-command, and together they tackle a range of crimes with more far-reaching consequences than those dealt with by the Honolulu Police Department, including terrorism and serious organized crime.