In an updated remake of the 1968 original series, Detective Steve McGarrett returns home to Oahu to investigate his father\'s murder and Hawaii\'s governor convinces him to stay and head up a new team with no rules and no red tape. Detective Danny \"Danno\" Williams joins the team in order to keep the island safe for his 8-year old daughter. Also joining the team is Chin Ho Kelly who was wrongfully accused of corruption and Chin\'s cousin Kono who is fresh out of the academy. While running the team, McGarrett also tries to repair his relationship with his estranged sister Mary Ann and continues to look for closure on his father\'s case.
Cast: Alex O\'Loughlin, Scott Caan, Daniel Dae Kim, Grace Park, Teilor Grubbs, Taylor Wily, Taryn Manning, Jean Smart, Will Yun Lee, Kelly Hu, Michelle Borth, Blaine Kia, Paul Edney
Danny is abducted and badly wounded by Wo Fat's wife, who is after the cypher Steve's mother left him. Also, Steve finally solves the case his father left for him 10 years ago.
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 an anonymous good Samaritan who's in the crosshairs of some very dangerous people.
The team investigates a scheme to rob tourists; Tani helps Girard Hirsh prove the innocence of his elderly uncle when he's suspected of murder; Tani and Junior work on the nuances of being in a new relationship.
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.
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.
Harry Langford helps Five-0 investigate a series of murders that follow the plot of a fabled unpublished crime novel from the 1920s. Also, Tani and Junior's friendship takes a meaningful new turn.
On Valentine's Day, Tani and Noelani are held hostage during a convenience store robbery. Also, Five-0 investigates the murder of a Thai diplomat whose wife confesses to the crime, but Danny suspects she's covering for the real killer.
When Grover's niece, Siobhan goes missing from the police academy and it's discovered her boyfriend is an undercover member of the Yakuza, Adam may be her only hope of rescue.
Soon after Danny meets the girl of his dreams, they get into a potentially fatal car accident in an area far from help. Also, McGarrett enlists Quinn and Tani to help when Eddie the dog suddenly shows signs of PTSD.
Grover and Five-0 investigate a murder at a private golf course involving a man who was frozen to death in the locker room's cryo-chamber. Also, McGarrett tags along with Danny when he tracks down the father of a boy who has been bullying Charlie.
Five-0 enlists the help of Thomas Magnum to retrieve a stolen list of undercover CIA agents.
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 – Wo Fat. Also, after Adam's ordeal in rescuing Tamiko and reconnecting with the Yakuza, he makes a bold decision about his future with Five-0.
When Adam's girlfriend, Tamiko is kidnapped right in front of him, he shuts out Five-O and breaks all the rules in order to get her back. Also, Five-O investigates three seemingly unconnected homicides.
It's Thanksgiving, and while Junior and Tani track down the thief who robbed his parents' home, Five-O investigates the murder of a beloved philanthropist and the theft of his ultra-valuable koa tree. Also, Danny moves in with McGarret.
Five-O teams up with a DEA agent to search for a killer whose plane crashed in the jungle with $10 million worth of heroin on board. Also, Grover is thrilled when his niece Siobhan comes to try out for the university of Hawaii basketball team.
When the CIA informs McGarret that his mother has gone rogue on her undercover mission and may have killed her partner, Steve goes solo to Mexico to bring her home and prove her innocence.
A deadly hit-and-run involves a driverless car carrying heroin; Tani and Quinn are stuck with a pair of YouTubers who are brought on a ride-along.
Five-0 investigates a deadly home invasion after an extremely dangerous prisoner escaped from the basement. Max returns to the island with a guest.
Five-0 enlists imprisoned hacker Aaron Wright to help when a young girl is reported kidnapped.
A plane that mysteriously crashed into the Pacific in the '80s is found, but with a recently murdered scuba diver inside; McGarrett and Quinn zero in on who planted the bomb in his garage; McGarrett formally asks Quinn to join the team.
Tani and Junior must plot an escape for themselves and several civilians after they become trapped inside a deadly tunnel collapse; Eddie the dog sniffs out a bomb that has been planted in McGarrett's home.
A new ally helps McGarrett and the team when mob bosses on the island are targeted by an assassin; the team says goodbye to one of its own.