Alicia awakens in her bed to find another body with a chess piece in his mouth beside her. The team hunts for a cartel boss whose soldiers are gunning for a member of the team. Kono reconnects with Rosie.

Five-0 must work with rogue MI-6 agent Harry Langford to find a terrorist planning to cause nuclear reactors across Europe to meltdown. Also, McGarrett and Danny ask retired FBI profiler Alicia Brown to help them find their serial killer vigilante.

When the bodies of two serial killers are found on Five-0 property with chess pieces in their mouths, McGarrett and the team hunt for a vigilante as fear grows that tourists aren’t safe in Hawaii.

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.

Trapped inside a dilapidated building in Oahu’s Chinatown, Five-0 must protect a wounded Gabriel and plan their escape when enemy gunmen storm the building looking to kill him and anyone who gets in their way.

When a woman is murdered in her home, Five-0 learns that one of their own has a deep connection to the victim’s young daughter.

Five-0 tries to save a kidnapped college student from a dangerous vigilante. Meanwhile, Max, Kamekona and Flippa fight to survive after being shipwrecked.

Five-0 goes on a manhunt when a deliberate chemical spill enables six dangerous inmates to escape, including Kono’s husband, Adam.

While Five-0 investigates the theft of a high tech, indestructible suit built for the U.S. military, Jerry helps his sister try to save a captive elephant.

A case from 15 years ago forces Grover to take his family on the run when a dangerous mob boss tracks him down to seek revenge.

When a man is found left for dead drifting off the coast of Oahu, Five-0 uncovers a deadly slave trade operating aboard an illegal fishing vessel. Also, while Danny is out with his children, his car is stolen so he commandeers a bus to chase down the thieves.

McGarrett and Five-0 must track down a Russian spy who has stolen a flash drive containing classified NSA information that puts the life of a member of their Ohana at risk. Also, McGarrett finally learns why Catherine left him, and Abby continues to conceal her actual mission from Chin and Five-0.

When Five-0’s sketchy confidential informant is accused of murder, McGarrett asks his old friend Odell Martin to defend him.

While Danny’s mother is questioned by the FBI, McGarrett partners with a young man with autism who may have information to help solve the murder of his only friend.

As Five-0 investigates a double homicide involving marital infidelity, McGarrett and the team recount their disastrous Valentine’s Day experiences.

Grover goes to Chicago to get a confession from Clay Maxwell; Chin and Kono are held at gunpoint by people who don’t know they are cops.

A special personal mission sends McGarrett’s Aunt Deb to Oahu. Unstable Japanese WWII bombs hidden on the island are stolen.

While McGarrett and Danny attend a couples retreat in Maui to work on their partnership issues, Kamekona’s dangerous past comes back to haunt him.

The brother of a promising local boxer is murdered, and the chief suspect is the outspoken reigning champion opponent from the mainland.

Five-0 goes back to school when a college professor is killed and Danny goes undercover as his replacement.

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.

McGarrett’s first date with Lynn on a deserted island turns deadly when a mob boss hiding there hunts them down in order to keep his location a secret. Also, Chin, Kono and Grover must race against the game clock to locate the father of a high school football star who will be murdered by a local gambler if his son doesn’t throw the big game.

It’s Halloween in O’ahu, and Five-0 must track down a serial killer inspired by Frankenstein. Also, Jerry calls Five-0 for help when an armed gang raids a blood bank, and Danny must track down Grace who lied and snuck out to a Halloween party.

Five-0 must interrogate members of a stunt bikers gang to find a killer who escaped by jumping his motorcycle from one roof onto another. Also, the team prepares to race in a Tough Mudder competition.

Five-0 investigates when a wealthy recluse is found dead in a remote field with nearly one million dollars in counterfeit bills. Also, Adam is kidnapped by the Yakuza and forced to torture one of Gabriel’s men.

While Five-0 investigates a scuba diver’s death from a gun recently used in another murder, McGarrett prepares to propose to Catherine.

Five-0 investigates when a bomb squad is attacked and the culprit threatens to detonate additional hidden explosive devices unless arsonist Jason Sinclair is released from prison. Also, after Adam returns from the hospital, Kono realizes that they are being watched, and McGarrett prepares to take his relationship with Catharine to the next level.

A murder leads Five-0 to investigate a centuries-old Oahu palace raid involving pirates, buried treasure and a killer who is using a stolen painting as a map. Also, the morning after their wedding, Kono and Adam are threatened and tortured by Gabriel, and Danny shows concern for McGarrett regarding Catherine’s return to the island.

On the eve of Kono’s wedding to Adam, Five-0 must stop a fanatical patriot intent on starting a new war on terror by detonating stolen nuclear warheads and framing a terrorist leader.

While Five-0 investigates the murder 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.

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.

When a woman is found murdered 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 killer. Also, Jerry witnesses a woman’s kidnapping on the streets of O’ahu.

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 off the island.

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.

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.

McGarrett enlists Joe’s help after Danny and Chin are arrested for deadly past transgressions.

McGarrett and Danny work on their relationship while they stakeout a woman’s apartment after she escapes following a diamond robbery.

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.

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.

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.