While McGarrett sits in prison awaiting trial for the murder of the governor, Danny brings him a surprise visitor to help clear him. Meanwhile, Kono is suspended for the force, pending an internal investigation.
Gov. Denning assigns Officer Lori Weston to Five-0 to make sure McGarrett and team follow the new rules set by him and also apply her excellent profiling skills to the task force. Meanwhile, as Five-0 investigates the kidnapping of a teenage paddleboard champion, Internal Affairs Capt. Vince Fryer continues his interrogation of Kono.
At his mentor's request, McGarrett persuades Max to redo the autopsy on a SEAL, thought to have committed suicide, in order to investigate his murder. Meanwhile, Chin Ho worries about Kono hanging out with a group of dirty ex-cops, including Frank Delano.
The FIVE-0 take to the beautiful waters off Hawaii to investigate the murder of a deep sea diver known for his valuable shipwreck finds.
The FIVE-0's investigation into the murder of the state's women's volleyball coach leads them to find out more bad news about Kono, and Chin Ho reconnects with his former fiancée, Malia.
The FIVE-0's investigation into the murder of a wealthy restaurant owner causes McGarrett to take part in a charity MMA fight to the finish. Meanwhile, NCIS Agent Kensi Blye lends her expertise to McGarrett and Lt. Commander White when they ask her to examine a video of McGarrett's father.
When the Five-0s investigate the murder of a young couple filming a spooky documentary about a traditional Hawaiian burial site, they are threatened by a drifter who puts a curse on Danny.
The FIVE-0's investigation into the suspicious plane crash and death of a customs agent takes an unexpected turn when it is revealed that the victim was dead before takeoff. Meanwhile, Danny finds himself the proud caretaker of an orphaned dog.
When the Five-0 discover a John Doe in the trunk of a stolen car, they not only have to find a killer, but also need to figure out who the physically-altered victim was. Meanwhile, a homeless Danno is sleeping on McGarrett's couch.
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.
McGarrett and the Five-0 search for a busload of kidnapped school children as well as the people responsible.
On the eve of Chin Ho's wedding to Malia, the Five-0's investigation into a man left for dead in an abandoned WWII bunker crosses paths with Capt. Fryer's case of a Jane Doe.
When the Five-0 determine that the murder of a teenage girl was a professional hit, they must first find out why she was targeted before they can find her killer.
McGarrett is rocked to his core when Chin Ho tells him some shocking news about Joe White. Meanwhile, Danny plays mid-wife for his ex-wife when she goes into early labor.
Dirty cop from Danno's past comes to the island to exact revenge on Danno and his family for ruining his life, forcing the Five-0 to find a way to help their teammate.
When Five-0 nearly causes an international incident while on a case, Lt. Governor Denning tells them one of the team members will pay for it with their job.
Five-0 investigates the murder of a man dressed as a Hawaiian NaKoa warrior found in the jungle near the site of a historical war reenactment.
Five-0 crosses paths with Tony Archer, a retired NYPD bomb expert who is now a private investigator on Oahu, when they investigate the death of famous talk radio DJ Bobby Raines.
When McGarrett's sister is arrested for trying to smuggle $20 million worth of conflict diamonds, he and Chief Fryer reach out to August March, an ex-con who served 30 years for diamond smuggling, to help arrange a sting operation.
Murder case hits close to home for Max when he is convinced that The Trashman, a serial killer with ties to his past, is on the loose. In order to convince Five-0 of his suspicions, Max reveals shocking information about his childhood.
Five-0 and the NCIS: Los Angeles task force team up in Hawaii when there's a suspect on the loose who is threatening to release a deadly virus into the population.
Just as McGarrett finally gets his hands on his arch nemesis Wo Fat in a special ops raid, he's blindsided when he finds that the Japanese Yakuza is hot on their trail and wants them both dead.
Five-0 is in hot pursuit of a shooter who guns down one of their own, while another team member is forced to choose which of their kidnapped loved ones will live.