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.
(Belief) A Hawaiian luau turns into a nightmare when the body of a dead cop, who turns out to be Danny's ex-partner from the Honolulu P.D., is found in the barbeque pit. Five-0's dogged investigation into the murder matches them against Internal Affairs, dirty cops and Hawaii's most powerful cocaine cartel.
(Shore) While hiking in a remote area of the jungle to see the famed petroglyphs, McGarrett and Danny instead find a homicide victim. Meanwhile, their aunt’s failing health leads Kono and Chin Ho to visit home, where Kono finally learns the truth about the scandal that ended her cousin’s career with the Honolulu Police Department.
(Until the End is Near) With the invaluable information that was shared by Agent Jenna Kaye, Five-0 is closer than ever to capturing Wo Fat. Their mission takes an abrupt turn, however, when Danny is exposed to a lethal neurological agent that presents an even greater threat: bio-terrorism on the island.
(Trust) When Five-0 gets too close to the truth about Wo Fat and his associates, the criminal mastermind retaliates by trying to destroy the team. They’ve always played by their own rules, but when the Governor can no longer protect them, it’s time for Five-0 to pay the consequences of their actions.
(Taken) 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.
(The Good Fight) 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.
(Death Wish) Max and his crush get put in harm’s way when a botched bank robbery leads the team to determine that the criminals had very unexpected motives. Meanwhile, Danny is stuck with the tough task of coming to the rescue of the most beautiful women in the world when a stalker goes after a Victoria’s Secret model.
(Searching for the Truth) 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.
(Sharing Traditions) 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.
(Do Not Disturb the Water That Is Tranquil) 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.
(Ashes to Ashes) 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 Catherine to the next level.
(Day Trippers) 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.
(Assets) 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.
(The Burden) Five-0 investigates the 10-year-old cold case of a missing teen when a boy suffering from PTSD undergoes hypnosis and realizes he may have witnessed her murder. Also, Danny’s sister, Bridget, visits Oahu for a business conference, and he suspects that she may be getting too close to a co-worker.
(Unfolded by the Water are the Faces of the Flowers) The murder of two tourists leads Five-0 to a man suffering from multiple personality disorder, where one of them becomes violent and another is a child. McGarrett is accompanied on the case by a stress management consultant, whom Danny and the others have hired to help him manage his health.
(The Children of Kalaihaohia) When the corpse of a diamond smuggler is stolen from a graveyard, Five-0 tracks down his partner, Voss, who will stop at nothing to retrieve their latest batch of contraband. Also, Adam recruits a new confidential informant, Jessie Nomura, Tani gets a devastating call, and McGarrett tasks Pua to find his and Danny's stolen tools.
(A Coral Reef Strengthens Out into Land) McGarrett and Danny investigate the murder of a private detective whose client was killed the same way, and Adam sends Jessie into a dangerous situation with disastrous consequences. Also, Danny’s uncle, Vito, comes to town to help Danny and McGarrett get their restaurant up and running.
(To Do One's Duty) The ex-wife of the man who shot Danny comes to Oahu and reveals how Danny’s protection during a dangerous domestic dispute when he was in New Jersey helped save her life. Also, Tani and Junior are assigned to walk the beat as uniformed officers for the day, and Adam is framed for the murder of the crime boss he has been tracking.
(Kind is the Bird of Kaiona) Catherine Rollins recruits McGarrett and Jerry to help her track down a uranium deposit thought to be hidden on an abandoned Hawaiian island before a suspected terrorist can make dirty bombs with it. Also, when Junior falls and is trapped in a ravine, he reflects on his estranged relationship with his father.
(The Answer to the Riddle is Seen) Harry Langford enlists McGarrett and Danny’s help to track down Lady Sophie, a teenage British royal who has run away while under his protection. Also, Grover, Tani and Junior work a 25-year-old murder case after a mysterious Betamax tape arrives at 5-0 headquarters.
(The Tough Branch That Does Not Break in the Kona Gale) McGarrett joins Junior and his SEAL Team on a high risk covert mission to capture an elusive target who is holding his mentor, Joe White, hostage. Also, Gerard Hirsch and Kamekona help Grover and Tani on a murder case involving masterpieces stolen by the Nazis during WWII and Tani makes a shocking discovery,
(Cocoon) 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.
(When the Sea Draws Out the Tidal Wave, the Rocks Where the Cowries Hide Are Exposed) Crime spikes when a heat wave hits Oahu, causing McGarrett and Danny to hunt down a bank thief, and Tani and Junior’s car is stolen while they’re on duty. Also, Grover plays the golf game of a lifetime, and Kamekona incites a riot by price-gouging on his shave ice.
(Is Borne on the Back; Is Borne in the Arms) McGarrett crosses the line and is arrested while investigating the death of his former SEAL buddy, who died while making an emergency landing on an aircraft carrier, and the only survivor is a baby. Also, Adam returns to Oahu with some devastating news about his marriage.
(The Smoke Seen in the Dream Now Rises) McGarrett investigates a cold case from the 1940s, one that his grandfather and the famous Honolulu detective Chang Apana worked on, and he tries to deduce how the case could have been solved. Also, McGarrett and Danny get ready for the opening of their restaurant.
(Gone on the Road from which There Is No Returning) Still reeling from the murder of one of their ohana, Steve and Catherine, along with Danny, Junior and some old friends, Harry Langford and Wade Gutches, hunt down the killer. Also, Tani and Grover investigate when a bag of human bones, discovered inside an abandoned storage locker goes missing.
(Made Prisoner by the Reign of the Rain) As a dangerous hurricane hits Oahu, Five-0 is tasked with protecting El Diablo, a captured serial killer who is being hunted by an assassin. Also, Tani’s civilian safety check during the storm turns deadly and Rachel and Charlie evacuate to Danny’s house, where the ex-spouses reminisce.
(He Who Eats 'ape is Bound to Have His Mouth Itch) Tani and Junior go undercover at a gym to track down a deadly batch of steroids that’s killing users, before the drugs claim any more victims. Also, Danny and McGarrett sub as bodyguards for Danny’s high maintenance ex-mother-in-law, Amanda Savage, a wildly famous romance novelist with whom he has never gotten along.
(The Octopus of the Deep Spews its Ink) Five-0 investigate the murder of a window washer and find that the victim is actually a renowned street artist who may have a politically motivated bounty on his head. Also, Grover and Adam look into the murder of a gambler, and Junior helps his father when they are reminded of his sister’s death.
(Knocked Flat by The Wind; Sudden Disaster) Tani and Junior must plot an escape for themselves and several civilians after they become trapped inside a deadly tunnel collapse, while Five-0 investigates the cause and culprits of the cave-in. Also, Eddie the dog uses his field experience and sniffs out a bomb that has been planted in McGarrett’s home.
(Passing Time Obscures the Past) Five-0 investigates when a plane that mysteriously crashed into the Pacific in the ’80s is found, but with a recently murdered scuba diver inside. Also, as MacGarrett and Quinn zero in on who planted the bomb in his garage, and he formally asks her to join Five-0, she is arrested for money laundering.
(All Knowledge is Not Learned in Just One School) McGarrett and the team investigate when a deadly hit-and-run involves a driverless car carrying heroin, and what could be a new means for delivering drugs. Also, Tani and Quinn are stuck with a pair of YouTubers who are brought on a ride-along with Five-0.
(To Return Evil for Evil) When Five-0 investigates a tourist helicopter that was shot down by a missile, they trace the stolen artillery to a ghost from McGarrett’s past. Also, After Adam’s ordeal in rescuing Tamiko and reconnecting with the Yakuza, he makes a bold decision about his future with Five-0.
(Lost in the Sea Sprays) While Five-0 investigates a murder on a cargo ship where pirates impersonated the Coast Guard to board the boat, Adam finally gets the evidence he needs to take down the Island's Yakuza operation once and for all. Also, Quinn helps Noelani when she suspects that her uncle didn't die of natural causes.
(Home Go The Very Tough Lads of The Hills) Five-0 investigates when a rancher is murdered after he uncovers human skeletons on his property where legend says that Civil War-era gold coins were buried. Also, Quinn's former stepdaughter, Olivia, reaches out to her for help after her father doesn't come home.
(He Cannot be Caught for He is an Ulua Fish of the Deep Ocean) After Steve receives a posthumous letter from his mother that contains a cypher, Danny is attacked by someone willing to kill to steal it. Also, Five-0 must help Lincoln Cole, an anonymous good Samaritan who’s in the crosshairs of some very dangerous people.