Episode 1 : La O Na Makuahine
Following McGarrett's mother's (Christine Lahti) surprise return and Chin's gut-wrenching decision in last season's finale cliffhanger, the team is determined to track down Wo Fat and Delano for killing an important member of their family.
Episode 2 : Kanalua
McGarrett asks Catherine for help in locating his mother and the team calls on August March for his assistance when an art heist turns deadly. Ed Asner guest stars.
Episode 3 : Lana I Ka Moana
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.
Episode 4 : Popilikia
Doris McGarrett pays an unexpected visit to her son while the team investigates the death of a polo player who literally loses his head. Christine Lahti guest stars.
Episode 5 : Mohai
It's Halloween in Hawaii and the clock is ticking when a grisly murder leads the team to a ritualistic killing, and evidence suggests that the killer will soon strike again.
Episode 6 : I Ka Wa Mamua.
When is forced to remain completely still while bomb technicians disarm a bomb that he accidentally activated, 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. Sydney Tamiia Poitier, Terrance Howard, rapper T.I. and Kendall Howard guest star.
Episode 7 : Ohuna
While the team investigates the murder of a young computer hacker, McGarrett tries to stage a long-needed reunion between his mother and sister.
Episode 8 : Wahine'inoloa
McGarrett plays cat and mouse with a smart and seductive therapist he believes murdered her patient. Meanwhile, Catherine must hunt down one of Doris's old targets who is now seeking revenge. Vanessa Marcil and Carlos Bernard guest star.
Episode 9 : Ha'awe Make Loa
Max and his crush 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. Victoria's Secret Model Behati Prinsloo, actress Rumer Willis and actor C. Thomas Howell guest star.
Episode 10 : Huaka'l Kula
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. Tom Arnold guest stars.
Episode 11 : Kahu
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 Oahu. George Takei guest stars.
Episode 12 : Kapu
The mystery begins when the team must investigate the death of an O'ahu State University professor; whose boss, teaching assistant and a student who he busted for cheating are all viable suspects.
Episode 13 : Olelo Ho'opa'I Make
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. Lindsay Price guest stars.
Episode 14 : Hana I Wa 'Ia
On the eve of an election, the Governor asks 5-0 to discreetly investigate the murder 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.
Episode 16 : Kekoa
Five-0 investigates the murder of a Lua master and McGarrett hires a private investigator to follow his mother. Christine Lahti returns as Doris McGarrett, Treat Williams guest stars as Mick Logan and Summer Glau guest stars as Maggie Hoapili.
Episode 18 : Na Ki'i
When a murder victim falls where Dog The Bounty Hunter is apprehending a suspect, Five-0 sends Catherine in undercover at the local roller derby to find the culprit. Bounty Hunter Duane "Dog" Chapman and his wife Beth Chapman guest star.
Episode 19 : Hoa Pili
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.