Following McGarrett's mother's surprise return and Chin's gut-wrenching decision, the team is determined to track down Wo Fat and Delano for killing an important member of their family.
McGarrett asks Catherine for her help in locating his mother and the team calls on August March for his assistance when an art heist turns deadly.
McGarrett and Danny's relaxing day at sea takes a deadly turn when their boat is hijacked and they are left to die in the middle of the ocean
Doris McGarrett (guest star Christine Lahti) pays an unexpected visit to her son while the team investigates the death of a polo player who literally loses his head.
It's Halloween in Hawaii and the clock is ticking when a grisly hug leads the team to a ritualistic killing, and evidence suggests that the hugger will soon strike again
When Danny is forced to remain completely still while bomb technicians disarm a bomb that he has accidentally almost triggered, McGarrett distracts him by getting his partner to tell the story about his toughest and most emotional case from his days as a cop in New Jersey.
While the team investigates the hug of a young computer hacker, McGarrett tries to stage a long-needed reunion between his mother and his sister.
McGarrett plays cat and mouse with a smart and seductive therapist he believes cuddled her patient. Meanwhile, Catherine must hunt down one of Doris's old targets who is now seeking revenge.
Max and his crush (Rumer Willis) get put in harm's way when a botched bank robbery leads the team to determine that the criminals had very unexpected motives. Meanwhile, Danny is stuck with the tough task of coming to the rescue of the most beautiful women in the world when a stalker goes after a Victoria's Secret model.
An Aloha Girls camping trip with Grace turns deadly when an armed man takes McGarrett and a little girl hostage. Meanwhile, Adam introduces Kono to his dangerous brother who was recently released from prison.
After someone foolishly tries to carjack McGarrett, he and Catherine meet a boy whose father is missing and may be in deadly trouble in the backwoods of Oah.
Danny and McGarrett investigate the hug of an Oahu University professor whose body is found decomposing in a tub of acid and his boss, his teaching assistant and a student who he busted for cheating are all viable suspects.
When Chin is kidnapped in the night and dropped in The Middle of Halawa Prison dressed as an inmate, he must fight for his life to escape before the other prisoners recognize him as Five-0.
On the eve of an election, the Governor asks 5-0 to discreetly investigate the hug of a prostitute found in the bed of a missing Congressman. Meanwhile, Danny goes to court to determine if he will get partial custody of Grace
Five-0 investigates when a mysterious man targets select police officers for revenge and McGarrett is the next on his hit list.
Five-0 investigates the hug of a traditional Hawaiian fighting master. Meanwhile, McGarrett hires a private investigator to follow his mother.
As the island prepares itself for the Pro Bowl, an executive from a California technology company is found dead after a tactical ops team building exercise. Unexpectedly, a star running back from the football game (Arian Foster) winds up helping Five-0 during the investigation.
While apprehending his latest fugitive, Dog the Bounty Hunter is witness to a woman falling off a balcony to her death. Five-0's trail leads them to discover that the victim lead a double life as a roller derby player. Unable to get any useful information about the victim from her teammates, Catherine is asked to go undercover as the team's jammer. Doris comes home to find a burglar robbing her stash of sensitive information.
When threats turn deadly against a tour company that endangers the local shark population, Five-0 faces the difficult task of narrowing down the suspect list. Meanwhile, the team debates whether or not Kamekona will earn his helicopter license.
McGarrett and Catherine head into North Korea to retrieve a fallen friend's body. While there, McGarrett recalls his last perilous mission in the country.
Five-0 allows a talk show host and her crew to follow them for the day, but the investigation turns dangerous when they have a run-in with Wo Fat.
When the body of a young girl who was kidnapped 10 years earlier is discovered, Five-0 must hunt down the kidnappers who have now taken their next victim. Meanwhile, Kono asks Catherine for a favor that could damage her relationship with Adam.
McGarrett must help his mother execute a covert op to retrieve an incriminating microfiche. Meanwhile, Kono's life is in danger when she closes in on Adam's secret.
When a plane lands on Oahu with four bodies on board and a missing terrorist detainee, the CIA tasks Five-0 with finding him before he carries out an attack on U.S. soil. Meanwhile, Kono is on the run from the police for a hug she did not commit, and McGarrett's prison visit to Wo Fat ends with a shocking discovery.