Adam’s mission to take down organized crime on the Island goes sideways when deadly chlorine gas he was using to bait a big fish falls into the wrong hands. Also, Adam begins to doubt Jessie’s allegiance.

Tani and Junior go undercover as prospective parents in order to infiltrate a private school where the headmaster was murdered. Also, Adam’s life is on the line when he is held captive and forced to produce a hidden massive amount of money.

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.

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.

When a man accused of killing his wife threatens to commit suicide, Grover reveals how he too was once on the brink of taking his own life.

When an FBI agent who was cracking down on organized crime is killed, McGarrett rounds up every gang-related criminal on the island to find the culprit. Also, McGarrett tasks Adam with forming a new division within Five-0 to take on organized crime.

It’s Christmas Eve and Danny tells Charlie a bedtime story about a recent Five-0 case involving criminals dressed as Santas and a holiday miracle.

When Danny is shot while quarantined in the hospital with McGarrett, Tani and Junior, he’s left unconscious and clinging to life, imagining a future for everyone in Five-0.

When investigating a deserted yacht adrift at sea, McGarrett, Danny, Tani and Junior are exposed to a deadly bioweapon and the rest of Five-0 have only eight hours to find an antidote.

McGarrett poses as a pilot to investigate a plane crash that led to the death of a pilot in an air race.

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

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.

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.

The lives of Five-0’s informants are in danger when the HPD system is hacked and one ends up dead, forcing McGarrett to enlist the help of hacker Aaron Wright (Joey Lawrence), who he just imprisoned

Five-0 enlists the help of an old friend when the boss of a major crime family is murdered, triggering revenge killings across the island. Also, MacGarrett and Danny begin sorting out particulars in their new restaurant venture,

McGarrett and Five-0 work with an injured police dog who is the only witness to an ambushed drug bust. Also, McGarrett is visited by Junior Reigns, a former SEAL, who is looking to join the task force.

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

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.

When McGarrett gets a tip that someone is plotting a terrorist attack on Oahu, Five-0 searches for those behind it before it’s too late. Also, Chin and Abby have a very difficult decision to make.

Danny protects a coma patient showing signs of waking who was the key witness from his last HPD case before he met Steve and joined Five-0.

While working the murder case of one of the last survivors of the USS Arizona, McGarrett learns about his grandfather’s important role at Pearl Harbor. Also, Adam uncovers bone fragments at his new construction job and asks Jerry to help him discreetly investigate.

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.

Five-0 helps PI Harry Brown work the case of a kidnapped wealthy woman whose husband may have something to hide. Also, Rachel tells Danny that she is getting a divorce from Stan.

McGarrett and Kono suspect that an abused young girl may be the victim of a sex trafficking ring on the Island. Also, Chin and Grover investigate a murder at a sober living facility.

MacGarrett and Danny finally track down the missing uranium, which has been used to build a bomb located in the middle of the jungle. Now, they must carefully extract the unstable explosive through treacherous terrain before it detonates.

McGarrett and Five-0 once again become entangled in the twisted mind games of serial killer Dr. Madison Gray when she stumbles into HPD covered in blood that matches Alicia Brown’s, and claims amnesia.

While McGarrett and Danno celebrate Valentine’s Day with their girlfriends, the rest of Five-0 investigates the murder of a man taking a class on how to land women.

When working a murder case involving the illegal practice of shark finning, Five-0 uncovers the possibility that a former Nazi war criminal may be hiding out in an old leper colony in Hawaii.

Five-0 must go up against an aggressive U.S. marshall, Lincoln, when a man wanted for murder escapes capture and seeks asylum in the sovereign land belonging to the Nation of Hawaii.

As Max prepares to say goodbye to his Five-0 ohana, they must investigate a murder during a police convention on the Island.

The team handles the fallout in Mexico after Chins problems, back on the Island Grover goes undercover and things get hot.

Five-0 races to Mexico where Chin puts his life on the line after his niece Sara is kidnapped.

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 (guest star Missy Peregrym), visits Oahu for a business conference, and he suspects that she may be getting too close to a co-worker, on HAWAII FIVE-0

When a conspiracy theorist with compelling evidence that JFK’s cabinet ordered his assassination is murdered, Five-0 investigate’s one of history’s most notorious unsolved mysteries.

While Danny chaperones Grace’s winter formal, terrorists seize the venue and hold everyone hostage in order to kidnap a diplomat’s son

Five-0 must free McGarrett’s mother, Doris, when Catherine informs them that she was captured and is about to be executed after attempting to free Wo Fat’s imprisoned father. Also, Chin loses his appeal to have Sara’s adoption delayed, and she must move to Mexico.

On Halloween, Five-0 investigates the murder of a medium with a checkered past who was apparently scared to death by a poltergeist. Also, Kono and Adam are kidnapped by what appears to be a death cult.

When a cache of guns is stolen from a gun range, Five-0 discovers the culprit is intent on making a dramatic and potentially deadly statement on gun violence. Also, Kono and Adam are finally reunited when he is released from prison,

Five-0 must find McGarrett and Alicia when they are kidnapped by the serial killer they’ve been hunting,

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.