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.

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.

Et etterforskningsteam som har frie tøyler, skal tørke ut all kriminalitet som bølger opp på Hawaiis vakre strender. En dykker blir funnet skutt og drept på havets bunn, og under etterforskningen finner Five-0 ut at det samme drapsvåpenet ble brukt til et annet mord. Samtidig forbereder McGarrett seg på å fri til Catherine.

Et etterforskningsteam som har frie tøyler, skal tørke ut all kriminalitet som bølger opp på Hawaiis vakre strender. Five-0 etterforsker drapet på en rik einstøing, som blir funnet drept på et avsidesliggende jorde sammen med nesten en million dollar i forfalskede sedler. Adam blir kidnappet av Yakuza-mafiaen, og tvunget til å torturere en av Gabriels menn.

Et etterforskningsteam som har frie tøyler, skal tørke ut all kriminalitet som bølger opp på Hawaiis vakre strender. Five-0-teamet avhører medlemmer av en stunt-motorsykkelbande, for å finne en morder som stakk av på motorsykkel ved å hoppe fra et atk til et annet. I tillegg forbereder teamet seg til å delta i en "gjørmebadkonkurranse".

Et etterforskningsteam som har frie tøyler, skal tørke ut all kriminalitet som bølger opp på Hawaiis vakre strender. Det er Halloween i O'ahu og Five-0-teamet etterforsker en seriemorder som er inspirert av Frankenstein. I tillegg konktakter Jerry Five-0 for å få hjelp når en bevæpnet gruppe angriper en blodbank. Danny på sin side leter etter Grace, som har sneket seg bort for å gå på Halloween-fest.

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.

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

Five-0-teamet etterforsker drapet av broren til en lovende bokser. Hovedmistenkte er hans neste motstander i ringen.

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.

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

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.

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

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.

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

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.

En mann blir funnet død, flytende langs kysten av Oahu, og Five-0-teamet avdekker en moderne slavehandel ombord på en ulovlig fiskebåt. I tillegg blir Dannys bil stjålet mens han er ute med barna sine, og han rekommanderer en buss for å jakte på tyvene.

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.

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.

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

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

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.

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.

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.