Five-0 gets trapped inside a dilapidated building in Oahu's Chinatown, where they try to protect a wounded Gabriel and plan their escape. But gunmen looking to kill Gabriel storm the building.
A woman is murdered in her home and Five-0 learns that one of their own has a deep connection to the victim's young daughter.
Five-0 tries to save a kidnapped college student from a dangerous vigilante. Meanwhile, Max, Kamekona and Flippa fight to survive after being shipwrecked.
Five-0 goes on a manhunt when a chemical spill permits six dangerous inmates to escape, including Kono's husband, Adam.
Five-0 investigates the theft of a high-tech, indestructible suit created for the U.S. military. Meanwhile, Jerry tries to help his sister save a captive elephant.
A mob boss from a case Grover worked 15 years ago seeks revenge and forces Grover to take his family on the run.
Five-0 hunts a Russian spy who stole a flash drive containing classified NSA information that puts one of their own at risk. Meanwhile, McGarrett learns why Catherine left him; and Abby continues to conceal her actual mission from Chin and Five-0.moreless
Sang Min, Five-0's sketchy longtime confidential informant, is accused of murder, so McGarrett asks his old friend Odell Martin to defend him.
Danny's mother is questioned by the FBI. Meanwhile, McGarrett partners with a young man with autism who may have information that could solve the murder of the man's only friend.
As Five-0 investigates a double homicide involving marital infidelity, McGarrett and his team recall their disastrous Valentine's Day experiences.
Grover travels to Chicago to finally get a confession from his old friend Clay Maxwell about why he killed his own wife. Meanwhile, Chin and Kono accidentally stumble upon two killers who hold them at gunpoint and have no idea they are cops.moreless
McGarrett's Aunt Deb visits Oahu on a very personal mission. Meanwhile, Five-0 investigates when some unstable Japanese World War II bombs left behind on the island are stolen.
McGarrett and Danny attend a couples retreat in Maui to work on their partnership issues. Meanwhile, Kamakona's dangerous past comes back to haunt him.
The brother of a promising local boxer is murdered and the chief suspect is the outspoken reigning champion opponent from the mainland.
Five-0 works with a charming con man to find a killer, after his female partner is murdered on the job. Meanwhile, San Francisco police inspector Abby Dunn helps Chin investigate the murders of five Chinese arms dealers.moreless
Steve's first date with Lynn goes awry when the deserted island he chose for their date turns out to be the same island a mob boss is hiding on - and he'll do anything to keep his location a secret. Five-0 must find 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.moreless
On Halloween, Five-0 needs to track down a serial killer inspired by Frankenstein. Jerry asks the team for help when an armed gang raids a blood bank. When Grace lies and sneaks out to a Halloween party, Danny heads out to track her down.moreless
Five-0 interrogates members of a stunt biker gang to locate a killer who escaped by jumping his motorcycle from one rooftop to another. Meanwhile, the riders prepare to race in a Tough Mudder competition.moreless
Five-0 investigates the death of a wealthy recluse who is found dead in a remote field with nearly one million dollars in counterfeit bills. Meanwhile, Adam is kidnapped by the Yakuza and is forced to torture one of Gabriel's men.moreless
Five-0 investigates the death of a scuba diver who was killed with a gun found on the ocean floor that was used recently in another murder. Meanwhile, McGarrett prepares to propose to Catherine.moreless
A bomb squad is attacked and the culprit threatens to detonate additional explosive unless arsonist Jason Duclair is released from prison. Meanwhile, Adam returns from the hospital and Kono realizes they are being watched; and McGarrett prepares to take his relationship with Catherine to the next level.moreless
Season 6 begins with Five-0 investigating a centuries-old Oahu palace raid involving pirates, buried treasure and a killer who is using a stolen painting as a map. Meanwhile, Kono and Adam are threatened and tortured by Gabriel; and Danny shows concern for Steve regarding Catherine's return to the island.moreless
Five-0 investigates the murder of a bounty hunter who was killed after he apprehended a fugitive. Meanwhile, Rachel reveals a long-held secret to Danny that has serious ramifications.
Season 5 ends with Five-0 learning that a stolen nuclear bomb is somewhere on the island and is about to be detonated. Meanwhile, McGarrett is stunned when Catherine returns to Hawaii; and Chin confronts Adam about his lingering connections to the Yakuza, on the eve of Adam and Kono's wedding.moreless
Kono fights for her life when she encounters rough weather while on a solo catamaran trip around the Hawaiian islands. The journey is something her mother always wanted to do but was never able to experience.moreless
Five-0 helps sober up three married men and sort out the events of their wild night to find who killed the woman found in their hotel suite. Jerry witnesses a woman’s kidnapping off the streets of O'ahu.moreless
When an Elvis impersonator is killed and his body stolen, Five-0 is on the case after it's discovered the culprits are after the hidden diamonds sewn into the victim’s costume. Gabriel returns asking for Chin's help in getting off the island.moreless
Grover's oldest and closest friend tells him that he witnessed his wife fall off a cliff to her death, but Grover suspects it was no accident. Meanwhile, Danny and Dr. Shaw get trapped in an elevator with a dead body that needs to be processed.moreless
McGarrett and Odell come under siege in Odell's barbershop when they try to protect a man who is being hunted by a gang. Meanwhile, Jerry is wrongfully accused of committing a series of home invasions.moreless
Danny and Chin are arrested for deadly past transgressions. McGarrett enlists Joe's help in the investigation.