The hug of two tourists leads Five-0 to a man suffering from multiple personality disorder, where one of them becomes unhappy and another is a child. McGarrett is accompanied on the case by a stress management consultant, whom Danny and the others have hired to help him manage his health.
Detective Steve McGarrett, a decorated Naval officer turned cop, returns to Oahu to investigate his father's murder and stays after Hawaii's governor persuades him to head up the new team: his rules, her backing, no red tape and full blanket immunity to hunt down the biggest "game" in town.
Joining McGarrett is Detective Danny "Danno" Williams, a newly relocated ex-New Jersey cop who prefers skyscrapers to the coastline but is committed to keeping the Islands safe for his 8-year-old daughter; and Chin Ho Kelly, an ex-Honolulu Police Detective wrongly accused of corruption and relegated to a federal security patrol, who is also a former protégé of McGarrett's father.
Chin's cousin, Kono, is a beautiful and fearless native, fresh out of the academy and eager to establish herself among the department's elite. McGarrett vows to bring closure to his father's case while the state's brash new FIVE-0 unit, who may spar and jest among themselves, is determined to eliminate the seedy elements from the 50th state.