It's Christmas time and Five-0 celebrates Chin's birthday until he receives a call that his niece Sara has been kidnapped in Mexico by the Mexican Drug Cartel and enlist the task force for their help to get her back. While, trying to rescue Sara, they found out that this was a revenge kidnap plan towards Five-0. Later on, Chin takes the matter into his hands and surrenders himself to the cartel in order to get Sara back leaving his life hanging in the balance.
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.