Steve McGarrett is summoned home to the island of Honolulu to bury his father after he is murdered by a madman. Governor Jameson wants Steve to head up a new elite police unit and she will give him full authority to get the job done. Initially he turns down the job, but when he meets the man in charge of the unit, he changes his mind.

McGarrett finds himself in need of the Five-0’s help when he goes to North Korea with Jenna Kaye to deliver a ransom to rebels who are holding her fiancé hostage. Meanwhile, the Five-0 investigate the murder of an investigative reporter who seems to have ties to Jenna.

The team goes after Wo Fat and Delano for the death of an important person. Steve must resolve the issues between him and his "dead" mother, once he finds her alive and well.

Chin is questioned about his father's murder and how his relationship with Malia and her family could have adversely affected the investigation.

McGarrett and Catherine travel overseas to Afghanistan to stop the Taliban from harming a young boy whose family saved Catherine's life years ago.

When Grover's daughter is kidnapped by an old nemesis, he is forced to help steal $100 million in order to get her back. Meanwhile, Wo Fat escapes prison and heads back to Oahu.

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.

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.

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 find McGarrett and Alicia when they are kidnapped by the serial killer they’ve been hunting,

McGarrett and Five-0 are captured and face certain death after tracking a dangerous nemesis to the Island of Lanai. Also, Grover takes his son to Chicago where he testifies against a dirty cop from his past.

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.

McGarrett and Danny recruit Tani Rey to join the task force when diabolical hacker Aaron Wright releases a dangerous arsonist from prison.

At Halloween, Five-0 must investigate a string of murders that mirror stories from well-known Hawaiian folklore. Also, Grover is called to visit a man hours away from execution who may hold the key to a case that has plagued Grover for years.

Junior and Adam back up McGarrett when a bank heist in progress forces Steve to make a potentially heartbreaking mistake. Also, Adam is forced to face an empty home without Kono

McGarrett and Five-0 take on the mob when a former boss is killed and Junior's friend Cammy Lin is on the run after witnessing the hit.

McGarrett and Five-0 discover a Russian spy ring hiding in plain site on Oahu when a Russian nuclear attack submarine appears on the coast of Waikiki. Also, Tani is conflicted by her unnerving discovery at Adam's house.

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.

After Steve receives a posthumous letter from his mother that contains a cypher, Danny is attacked by someone willing to kill to steal it. Five-0 must help Lincoln Cole, an anonymous good Samaritan who’s in the crosshairs of some very dangerous people.