After McGarrett and Wo Fat narrowly escape from maximum security, gunmen storm Five-0 headquarters, compromising Kono and Adam's secret location in Hong Kong and forcing McGarrett to break the law and turn on his own in order to find a kidnapped Catherine.

The investigation of a murdered pool cleaner leads the Five-0 team to a possible terrorist cell of radicalized students plotting an attack on U.S. soil.

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.

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 killer's surprising motives. Meanwhile, Chin puts his career on the line to help Danny get the money he needs to save his brother's life.

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.

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. The investigation uncovers the truth behind the disappearance of four reform school boys over 40 years ago. Meanwhile, McGarrett's beloved Mercury Marquis is stolen by an unlikely culprit.

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.

Five-0 must work with charming con man Hank Weber to find a killer when his female partner is murdered on the job. Also, San Francisco Police Inspector Abby Dunn comes to O’ahu and works with Chin to investigate the murders of five Chinese arms dealers.

In order to stop a meth epidemic on the Island, McGarrett and Danny go undercover as pilots, but when McGarrett is seriously wounded, Danny is forced to break their cover in order to save his partner’s life.

Five-0 races to Mexico where Chin puts his life on the line after his niece Sara is kidnapped.

Five-0 must go up against an aggressive U.S. marshall, Lincoln, when a man wanted for murder escapes capture and seeks asylum in the sovereign land belonging to the Nation of Hawaii.

McGarrett and Five-0 once again become entangled in the twisted mind games of serial killer Dr. Madison Gray when she stumbles into HPD covered in blood that matches Alicia Brown's, and claims amnesia.

McGarrett risks his life when Five-0 attempts their most dangerous rescue yet of young girls trapped in the sex trafficking ring they have been tracking this year. Also, Kono, deeply affected by the case, makes a life-changing decision.

When the corpse of a diamond smuggler is stolen from a graveyard, Five-0 tracks down his partner, Voss, who will stop at nothing to retrieve their latest batch of contraband. Also, Adam recruits a new confidential informant, Jessie Nomura; Tani gets a devastating call; and McGarrett tasks Pua to find his and Danny's stolen tools.

After Steve’s CIA agent friend is killed, McGarrett lets himself be captured by the group he thinks is responsible and endures a torturous sensory deprivation tank to find the killer. Also, Tani wrestles with whether or not she will tell McGarrett about the murder weapon she found at Adam’s house.

Crime spikes when a heat wave hits Oahu, causing McGarrett and Danny to hunt down a bank thief, and Tani and Junior's car is stolen while they're on duty. Also, Grover plays the golf game of a lifetime, and Kamekona incites a riot by price-gouging on his shave ice.

Thanksgiving brings Grover’s parents and brother Percy Jr. to Oahu for a visit tainted by sibling rivalry, and Five-0 investigates a thief who is crushed to death by an empty safe.

When the top salesperson for a beauty company/pyramid scheme is murdered, Five-0 sifts through a long list of possible suspects who would want her dead. Also, Adam befriends a homeless man estranged from his family.

Five-0 investigate the murder of a window washer and find that the victim is actually a renowned street artist who may have a politically motivated bounty on his head. Also, Grover and Adam look into the murder of a gambler, and Junior helps his father when they are reminded of his sister’s death.

Fugitive hacker Aaron Wright resurfaces to ask Five-0 for help when his co-workers at the NSA, which he has been working for, are all murdered. Also, Junior speaks at the parole hearing of the drunk driver who killed his sister.