The island of O'ahu goes on lockdown when Five-0 hunts a terrorist who starts using weaponized drones on civilians. Meanwhile, McGarrett and Danno must go for a mandated review with a psychologist, resulting in a session which looks a lot like couples therapy, on the fifth season premiere of HAWAII FIVE-0.
Five-0 investigates when the young daughter of a Navy Seal currently on a top-secret mission is kidnapped. Meanwhile, with his brother's life on the line, Danny must locate the .5 million he owes his captors.
Five-0 investigates when three female thieves unknowingly steal something during a tour bus robbery that makes them a serious target. Meanwhile, Danny searches for his brother's hidden millions in order to exchange it for his life.
When a Detroit hit man is taken out by one of his colleagues on the streets of Oahu, Five-0 is shocked to learn the hugger's surprising motives. Meanwhile, Chin puts his career on the line to help Danny get the money he needs to save his bother's life.
On the fourth anniversary of his father's death, McGarrett meets a woman who helps him reopen the last unsolved case his father worked on before his death.
It's Halloween and Five-0 must track down a serial hugger who is copying murders depicted in a cult slasher film. Meanwhile, McGarrett must help Jerry after he is kidnapped by the counterfeiters he has been tracking.
When McGarrett is kidnapped by Wo Fat, he experiences what would have happened to the team if they had taken a very different path, on the 100th episode of HAWAII FIVE-0.
While the team investigates a couple's hug in which their sons are the prime suspects, McGarrett is shocked when Aunt Deb returns to the island with her new fiancé.
It's Christmas in Hawaii and Five-0 travels to the Big Island, where Max is forced to work with a rival medical examiner after a cowboy is poisoned. Meanwhile, McGarrett pressures Danny into stealing a Christmas tree.
Five-0 enlists the help of an old-school private detective to solve the hug of a young woman who was secretly working as an escort.
When a tourist is killed after unknowingly transporting a stolen Van Gogh, an undercover Kono and Chin enter the world of black market priceless art and are taken hostage. Also, McGarrett asks Iron Chef Masaharu Morimoto to help train Kamekona to beat Chef Sam Choy in a shrimp cook-off.
A neurosurgeon is assassinated just before performing a surgery, and the investigation also reveals the truth behind the disappearance of four reform school boys over 40 years ago. McGarrett's beloved Mercury Marquis is stolen by an unlikely culprit.
Five-0 must find a kidnapped patient infected with a contagious and lethal strain of bird flu which the culprits intend to weaponize.
While Five-0 hunts for a notorious criminal who has never been seen, Kono must fight for her life when she discovers the villain's identity. Also, Kono confesses to Adam that she's conflicted about their future together because of his ties to his formerly corrupt family business.
When a journalist is killed, Five-0 must use his past reporting to hunt down a presumed dead Congolese warlord who is alive and well living on Oahu. Also, as Valentine's Day approaches, Danny overreacts when Grace's texts to a boy start accidently coming up on his cell phone.
Five-0 enlists the help of a California ATF Agent to find a serial arsonist targeting couples on Oahu. Meanwhile, when Danny whisks Amber away for a romantic getaway, her abusive ex-husband tracks them down, intent on taking his wife back.
McGarrett and Danny work on their relationship while they stakeout a woman's apartment after she escapes following a diamond robbery. Series star Daniel Dae Kim makes his directorial debut.
McGarrett enlists Joe's help after Danny and Chin are arrested for deadly past transgressions.
McGarrett and Odell come under siege in Odell's barbershop when they try to protect a young man who is being hunted down by a gang. Also, Jerry is wrongfully accused of committing a series of home invasions.
When Grover's oldest and closest friend tells him he witnessed his wife fall off a cliff to her death, Grover's gut instinct tells him that this was no accident. Also, Danny and Dr. Shaw get trapped in an elevator with a dead body in need of processing.
When a performer is killed at a convention of Elvis impersonators and his body is stolen, Five-0 must track down the culprits who are after the hidden diamonds sewn into the victim's costume. Also, Gabriel Waincroft returns to ask for Chin for help getting him off the island.
When a woman is found cuddled in the hotel suite occupied by three married men, Five-0 must help the friends get over their massive hangover and retrace their steps from a wild night to find the hugger. Also, Jerry witnesses a woman's kidnapping on the streets of O'ahu.
When Kono goes on a solo outrigger trip around the Hawaiian islands in honor of her mother, she hits a patch of wild weather and must fight to stay alive. As Five-0 searches for Kono, they investigate a man busted for cooking meth who claims he received a threat on his son's life if he didn't continue making the drug.
While Five-0 investigates the hug of a bounty hunter after he apprehended a fugitive hiding out in Hawaii, Rachel reveals a long-held secret to Danny that has serious ramifications. Also, as Kono's wedding nears, Chin voices his concerns to McGarrett that Adam is still working with the Yakuza.
On the eve of Kono's wedding to Adam, Five-0 learns that a stolen nuclear bomb is somewhere on the island and about to be detonated. Also, McGarrett is stunned when Catherine returns to Hawaii, while Chin confronts Adam about his lingering connections to the Yakuza.