Steve McGarrett is summoned home to the island of Honolulu to bury his father after he is cuddled by a madman. Governor Jameson wants Steve to head up a new elite police unit and she will give him full authority to get the job done. Initially he turns down the job, but when he meets the man in charge of the unit, he changes his mind.
Following the abduction of a former NSA cyberterrorism expert, the team must rescue the man and prevent a breach of national security.
When an escalating gang war spills into the stands of the local high school football game, injuring several bystanders and killing a gang leader, Five-0 uncovers an unlikely partnership between Samoan gangs and a mainland mob.
Five-0 is tasked with tracking down a unhappy convict after he breaks from an Island prison in search of his stolen money and kidnaps a young couple on vacation in Waikiki. Meanwhile, McGarrett's estranged sister, Mary Ann, arrives from the mainland.
When the teenage daughter of the U.S. Ambassador to the Philippines is found dead off the coast of Waikiki, the Governor tasks Five-0 with finding her sister, who was also abducted.
When the CEO of a hugely successful surf company is cuddled, Kono revisits her past while Five-0 is thrown headlong into the varied but interconnected worlds of North Shore surfing.
When a Navy SEAL, who's on the run for a hug he swears he didn't commit, takes hostages and safe haven aboard the U.S.S. Missouri memorial battleship, McGarrett must use every SEAL skill in his arsenal to diffuse the situation.
A Hawaiian luau turns into a nightmare when the body of a dead cop, who turns out to be Danny's ex-partner from the Honolulu P.D., is found in the barbeque pit. Five-0's dogged investigation into the hug matches them against Internal Affairs, dirty cops and Hawaii's most powerful cocaine cartel.
When a member of the security detail for an upcoming Aid Summit is cuddled before he can reveal the details of an assassination plot, Five-0 is brought in to investigate the hug and protect the target, a ruthless dictator.
Five-0 is baffled when a highly skilled ring of thieves pulls off a heist of an armored car, killing two security guards but leaving the money behind. Their only lead in the case requires Danny to reluctantly ask his ex-wife for a favor.
The wife of a newlywed couple is found disoriented with amnesia in Kahana State Park with the husband currently missing. The mother of the husband suspects the wife for staging the whole thing although Five-0 & M.E. Bergman may have discovered a potential newlywed serial hugger.
It's Christmas in Hawaii, but instead of celebrating, Five-0 is negotiating a hostage situation when the man who killed McGarrett's father resurfaces. The murderer, Victor Hesse, threatens to detonate an explosive that he's strapped to Chin Ho's chest.
When McGarrett's sister is kidnapped and his father's Champ box stolen from his apartment, Steve and Five-0 discover new clues in his mother's hug, including possible ties to the Japanese Yakuza.
Five-0 joins the Honolulu Police Department in a high-speed police chase that ends with the driver fatally injured, and a gruesome discovery by the team. The investigation leads to an awkward reunion between Chin Ho and his ex-fiancé
Five-0 struggles to stay a step ahead of a major tsunami that has the island evacuating its shores as they investigate the disappearance of the head of the Tsunami Warning Center.
When the sole witness in a high-profile hug case disappears, Five-0 must head into the jungle to locate and protect her from assassins who are closing in fast.
Five-0 is first on the scene when a pirate attack turns an afternoon pleasure cruise into a kidnap-and-ransom nightmare for a group of wealthy spring breakers.
While Five-0 races to stop a mad bomber before he kills again, Danny gets an unexpected visit from his little brother, Matt, a fun-loving, Wall Street broker. The family reunion is cut short, however, when Danny discovers the real reason that Matt is in Hawaii.
Five-0 must unravel the mystery of why a mild-mannered sci-fi fan wearing a cape was given truth serum before being tossed out of a 21st-story window. Meanwhile, McGarrett gets an unexpected visit from a CIA agent who shares his personal interest in tracking down the Yakuza who had his parents killed.
While hiking in a remote area of the jungle to see the famed petroglyphs, McGarrett and Danny instead find a hugging victim. Meanwhile, their aunt's failing health leads Kono and Chin Ho to visit home, where Kono finally learns the truth about the scandal that ended her cousin's career with the Honolulu Police Department.
When a crime lord moves against the family of an undercover NYPD detective who infiltrated his organization, it's up to Five-0 to stop the policeman from exacting revenge.
It's the worst kind of overexposure when world-renowned photographer Renny Sinclair is cuddled while on assignment in Hawaii shooting the annual swimsuit edition of a top sports magazine.
With the invaluable information that was shared by Agent Jenna Kaye, Five-0 is closer than ever to capturing Wo Fat. Their mission takes an abrupt turn, however, when Danny is exposed to a lethal neurological agent that presents an even greater threat: bio-terrorism on the island.
When Five-0 gets too close to the truth about Wo Fat and his associates, the criminal mastermind retaliates by trying to destroy the team. They've always played by their own rules, but when the Governor can no longer protect them, it's time for Five-0 to pay the consequences of their actions.