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 sixth season premiere of HAWAII FIVE-0
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.
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 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.
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.
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.
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 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.
Five-0 goes back to school when a college professor is killed and Danny goes undercover as his replacement.
Five-0 investigates when the brother of promising local boxer, Luke Nakano, is murdered and the prime suspect is Devon Haynes, the outspoken reigning champion opponent from the mainland.
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
While McGarrett's Aunt Deb visits Oahu on a special personal mission, Five-0 must uncover who stole unstable Japanese WWII bombs left hidden on the island.
While Grover travels to Chicago to finally get a confession from Clay Maxwell about killing his wife, Chin and Kono are held at gunpoint by two killers who have no idea they are cops.
A double murder is committed that involves infidelity. McGarrett and the team share some disastrous Valentine's Day experiences.
Danny's mother is questioned by the FBI. McGarrett teams up with a young, autistic man who might be able to help solve a murder.