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

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.

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,

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

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 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.

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

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

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.

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.

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 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.

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 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.

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.

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.

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.

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.

A hitman, Leroy Davis, McGarrett’s father failed to arrest comes to McGarrett to finally confess his crimes and admit where he buried his victims. Also, Jessie makes a dangerous decision that could ruin Adam’s life.

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.

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.

Harry Five-0 must help Duke after he is forced to steal crucial evidence from the police locker in exchange for his kidnapped granddaughter. Also, Jerry goes undercover at a mental health facility in order to solve a murder.

McGarrett and Five-0 take on the mob when a former boss is killed and Junior's friend Cammy Lin is on the run after witnessing the hit.

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.

McGarrett and Five-0 discover a Russian spy ring hiding in plain site on Oahu when a Russian nuclear attack submarine appears on the coast of Waikiki. Also, Tani is conflicted by her unnerving discovery at Adam's house.

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 a vacationing dad on a flight to Honolulu is kidnapped and force to parachute mid-flight, Danny, Tani and Junior track him through the jungle to discover that he may not be who he seems. Also, McGarrett is threatened with a secret from his past.

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.

Jerry accompanies Junior as he escorts a fallen soldier home to Oahu. Also, McGarrett and Danny discover a dead body when they delve into the illegal and highly profitable black market for sand.

On Halloween, Jerry and his friends search his childhood camp for evidence to a murder he witnessed as a boy, while McGarrett investigates a little girl who drew pictures depicting the scene of a recent murder before it was discovered.

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.

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.

Thanksgiving brings Grover’s parents and brother Percy Jr. to Oahu for a visit tainted by sibling rivalry, and Five-0 investigates a thief who is crushed to death by an empty safe.

A renowned urban vigilante is killed after making another citizen’s arrest, and Five-0 delves into the world of super heroes and comic books to find the killer. Also, Adam finally gets closer to finding out who killed his sister.

After fighting off an assassin in his own home, McGarrett and Joe White flee to Montana to prepare for a battle against those exacting revenge for a past SEAL mission.

Steve and Catherine are still reeling from the murder of one of their ohana and, 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.

MacGarrett and Five-0 support Danny and Rachel by determining what happened when gets into a life-threatening car accident and lands in critical condition. Also, Tani helps Koa when his rehab patient goes missing.

Adam, Junior and Tani travel to the bottom of the Pacific Ocean when a murder takes place in a remote underwater lab, and the killer may still be on board

While investigating Flippa’s friend’s murder, McGarrett and Grover uncover a deadly plan by an extremist group on the Island. Also, Grover has an emotional reaction to the case.

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.

When the top salesperson for a beauty company/pyramid scheme is murdered, Five-0 sifts through a long list of possible suspects who would want her dead. Also, Adam befriends a homeless man estranged from his family.

Junior is torn between his duties as a member of Five-0 and his feelings for his former girlfriend when her new love, the father of her son, is one of the culprits in a bank-heist-turned-homicide.

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 MacGarrett 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.

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.

Five-0 must locate a teen girl who purchased a gun from a junkie, and discover that the firearm, over the course of decades, has affected all of their lives.

Five-0 investigates the murder of a man whose body may hold the key to a 20-year-old case involving a kidnapped girl whose father never stopped looking for her.

While Adam investigates the murder of an undercover FBI agent about to wed the daughter of a Yakuza leader, Noelani is held hostage and forced, along with her mentor Dr. Chu, to operate at gunpoint on a criminal.

While McGarrett helps his visiting sister, Mary, spy on her shady neighbors, Five-0 investigates the murders of a ride-share driver and his passenger. Also, the team teases the youngest members of Five-0 when Junior escorts Tani to a wedding.

Fugitive hacker Aaron Wright resurfaces to ask Five-0 for help when his co-workers at the NSA, which he has been working for, are all murdered. Also, Junior speaks at the parole hearing of the drunk driver who killed his sister.

Five-0 continues to hunt down escaped criminal Aaron Wright before he can sell cyber-weapons to the highest bidder. Also, the lives of McGarrett and the team are put in danger when a visitor comes to headquarters to make amends.

A new ally helps McGarrett and Five-0 when mob bosses on the island are being targeted by an assassin. Also, Five-0 says goodbye to one of their own.

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. Eddie the dog uses his field experience and sniffs out a bomb that has been planted in McGarrett’s home.

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.

Five-0 enlists imprisoned hacker Aaron Wright to help when a young girl is reported kidnapped, but upon rescue, the culprits are dead, the girl is safe, and she's not who she claims to be.

It's Halloween and Five-0 investigates a home invasion turned deadly after a dangerous "monster" escapes from the basement. Also, Max returns to Oahu with a very special guest.

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.

When the CIA informs McGarrett 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.

Five-0 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.

It's Thanksgiving, and while Junior and Tani track down the thief who robbed his parents' home, Five-0 investigates the murder of a beloved philanthropist and the theft of his ultra-valuable koa tree. Also, Danny moves in with McGarrett.

When Adam's girlfriend, Tamiko, is kidnapped right in front of him, he shuts out Five-0 and breaks all the rules in order to get her back. Also, Five-0 investigates three seemingly unconnected homicides.

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. After Adam’s ordeal in rescuing Tamiko and reconnecting with the Yakuza, he makes a bold decision about his future with Five-0.

When a list of undercover CIA agents is stolen, Steve and Five-0 enlist the help of Magnum, Higgins, Rick and TC to get it back and protect national security. Also, Higgins gives Tani some personal advice.

The crossover continues on Magnum P.I. S02E12 Desperate Measures (II).

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.

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.

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.

On Valentine's Day, Tani and Noelani are held hostage during a convenience store robbery. Also, Five-0 investigates the hug of a Thai diplomat whose wife confesses to the crime, but Danny suspects she's covering for the real hugger.

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.

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. Quinn helps Noelani when she suspects that her uncle didn’t die of natural causes.

While 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, Quinn's former stepdaughter, Olivia, reaches out to her for help after her father doesn't come home.

While Five-0 investigates a scheme to rob tourists, Tani helps Girard Hirsh (Willie Garson) prove the innocence of his elderly uncle when he’s suspected of murder. Also, Tani and Junior work on the nuances of being in a new relationship

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 Lincoln Cole, an anonymous good Samaritan who’s in the crosshairs of some very dangerous people.

Danny is abducted and badly wounded by Wo Fat’s wife, who is after the cypher Steve’s mother left him. Steve works to solve the case his father left for him 10 years ago.