When a young female student is found murdered on campus, suspicions fall on her boyfriend but McGarrett senses that something is not right.

A baseball player, Lon Phillips, brings his backward son to Hawaii to escape threats on his life on the mainland.

A ten year old case is reopened when an archaeological dig unearths the skeletons of two murder victims.

Gangster Johnny Oporta arranges for his enemies to be murdered and then covers up his crimes by incinerating their bodies. McGarrett and the others must stop this murderous spree.

Vic Tanaka is murdering women and painting their faces to resemble a prostitute he once knew, who is now happily married. McGarrett and his team must find the killer before he does any more damage.

Five-O is up against a sophisticated gang who have come to Hawaii to cash $750,000 of traveller's cheques.

A hippie robs an embezzler of the key to a locker containing $250,000. Meanwhile, Danno is trying to contact the daughter of his Berkeley University landlady, who happens to be the hippie's girlfriend…

Young Vietnam veteran and marksman Billy Shem Jr. buys a rifle under false pretences and proceeds to a bunker at Diamond Head. He then takes pot shots at the people on the road and then the police who arrive. McGarrett must neutralise the threat he poses by any means possible.

While investigating the death of a security agent at an airport, McGarrett comes into contact with a gang who hijack cargo.

Five seemingly good citizens with different motives band together to steal $6,000,000 while McGarrett is away on Maui at a trial.

McGarrett finds holes in a convict's story and a husband becomes a suspect in the murder of his wife.

A policeman who was kicked off the force blames McGarrett and Five-O and plans to kill the Governor.

McGarrett must deal with the conflicts between four gangs of differing ethnic background, and try to uncover illegal activities.

A mob boss seeks revenge on a former boxer who smashed the hand of a novice to prevent him from ending up ruining his life in the boxing ring.

McGarrett and the team must find out who is behind a series of ecological stunts, when it is feared that a company executive will be their next target.

A veteran criminal who has already had dealings with Five-O escapes, and plans to steal millions of dollars from drug smugglers.

A woman attempts suicide in order to get her boyfriend to come out into the open and expose himself to an assassination attempt.

McGarrett is framed in an elaborate set up by Wo Fat, and has to contend with a foreign double amongst other problems.

Several faces from the past reappear as McGarrett must stop Wo Fat from carrying out his plan, a ninety second attack on a missile tracking base.

When a young woman is beaten and raped and a soldier is arrested for the crime, McGarrett begins to have doubts about his guilt.

An eccentric billionaire is accused of murdering a business associate, but will not leave his boat to defend himself against the accusations, allowing his associates to declare him mentally incompetent.

Three real estate crooks die horrible and mysterious shellfish related deaths, and McGarrett and the others must establish the link between them, and who has reason to want them dead.

McGarrett sets up a cordon of police around a young woman to capture her boyfriend who has escaped from jail, but all is not as it seems…

A young widow becomes part of a blackmail plot involving the murder of a Chicago mobster.

Danno goes undercover onboard a Navy ship to try and uncover how sailors are smuggling heroin onto the islands.

A psychotic man named Ralston is killing the wives of members of his army unit, and Five-O, including Kono on his last case, must stop him before he commits any more crazed attacks.

An Irish terrorist uses disguise and deception in order to be able to smuggle explosives for the Troubles.

McGarrett must solve both a mysterious kidnapping and the problem of having a nosy reporter analysing his every move.

When a Russian tennis star wants to defect, McGarrett must work to prevent an international incident.

McGarrett becomes involved in a love triangle between a young local man, a rich girl and her father who hates the Hawaiian origins of the boy.

A young doctor is suspected of having been involved in the murder of his mentor.

In order to find out the identity of the murderer of a union leader, McGarrett goes undercover as a longshoreman.

An up-and-coming young politician is blackmailed in order to affect his leadership of an congressional investigation.

A cryogenics institute comes under suspicion when an investigative writer becomes involved.

After a government agent is murdered, McGarrett must identify the traitor in a scientific facility.

When an astrologer visits McGarrett to inform him of a murderer with a terrible temper, his antagonism lessens when her assumptions seem to be partly true.

An assassin who doesn't know he's an assassin? Sounds like a punch line from "The Naked Gun," but it's the story of this episode, where a diplomatic courier with a briefcase chained to his wrist is hypnotized and programmed to rig the case with a bomb. When Danno goes undercover to ferret out the assassination ring, he himself is brainwashed and programmed to kill McGarrett.

McGarrett is the lone hold-out in a trial where the guilt of the accused seems certain.

Steve is framed on the orders of a gambling syndicate, and becomes involved with a woman who is part of the case.

Five-O must deal with the plans of a Neo Nazi organisation to kill Bobby Tamara, the ""Hawaiian Kennedy"".

When a street robber claims that he stole King Tutankhamun's mask for fun, McGarrett suspects there is more to the case than simple robbery.

McGarrett assists a convict in his escape, so that he can go back to his gang and provide Five-O with inside information.

Danno is surprised when he bumps into a former flame and even more concerned when she seems to be involved in criminal activities.

The death of a prominent politician reveals a strange love triangle.

When a preacher is attacked by a man convinced that he is responsible for his wife's death, Five-O investigate more closely and discover some less than godly motives.

Two rival mobs attempt to take control of the disco scene in Honolulu.

The rival gangs are on the brink of all out war, and Five-O must struggle to stop them.

When a robbed bank vault shows no signs of break-in, an inside job seems the likely solution. McGarrett's trail of clues leads him back to the builder of the vault and his wife...

Millicent Shand returns and claims that her niece's husband has faked his own death in order to get his hands on $500,000.

A vacationing heiress seems unconcerned when McGarrett warns her that someone is after her ruby.

When a photographer takes a picture of a politician making a deal with an underworld figure, he tries blackmail. However, he is not prepared for the ruthless nature of the mobsters.

A private detective is rescuing girls from prostitution, and using the opportunity to kill the pimps as well.

When the son of one of Steve's friends dies of an overdose, he goes after a doctor that he suspects of over-prescribing drugs.

The hunt for a high-rise killer is made more difficult for Five-O when a journalist offers to share his profits in exchange for the killer's story.

When a woman dies due to heroin packets bursting inside her and the Governor is implicated, McGarrett and Danno head off to Singapore to discover a smuggling operation.

Five-O must close the heroin smuggling operation to exonerate the Governor and catch the figures behind the scheme.

McGarrett finds himself stymied when Hawaiian nationalists and local underworld mobsters clash over a union election.

Labouring under a ban on cooperation by native Hawaiians because of a Kahuna, McGarrett must try to prevent war on the streets...

When the husband of a policewoman is gunned down by opportunist robbers, she resolves to catch them any way she can.

A group of high society men set out to see that justice is done - the catch being that it is justice on their terms only...

Jessica Humboldt, an astrologer and friend of Agnes DuBois, comes to McGarrett with news that a forthcoming match will be disastrous for a boxer. McGarrett must overcome his suspicions and crack the case.

Tony Alika and Guido Marioni, killer of Kimo's family, together hatch a plot to frame and embarrass the Five-O team by making them look stupid or corrupt.

When a woman is stalked by a strange figure, she seems to be seeing things and her friends are worried as to her mental health. However, events prove her case and an accomplice is revealed...

When two surfer bums use a gun to rob a shop, it starts off a trail of death and misery involving children, politics and blackmail.

A group of terrorists capture a female officer and use her to further their aims, and McGarrett and the team must find a way to take them out without endangering the life of Officer Dean.

A young man on vacation has strange visions that lead him to the site of an old murder and help him discover a lost family.

When two healthy young people die mysteriously, local traditions prevent post mortems, and a strange conspiracy is gradually uncovered when Truck seems to fall under the power of a Kahuna...

When a rich socialite is kidnapped, her husband insists that Five-O stay out of the case. However, his reasons may not all be on the level as events take a series of twists and turns...

McGarrett and Kimo must stop a gang of trained assassins from disrupting a meeting of energy ministers.

A aging crook decides to use dollar bill printing plates he made to raise cash for a charity, but he fails to realise the trouble that this will cause.

McGarrett is suspicious of an aide who arrives in Hawaii to retrieve millions of dollars held in trust for a Southern Asian state and he must prevent a daring gold robbery.

A gang of clever students use radio-controlled planes to execute the theft of Queen Liliokalani's jewels.

The murder of a Nazi-hunter and discovery of a World War II medal set McGarrett and the team on the trail of a Nazi war criminal living in Honolulu...

A group of seemingly harmless birdwatchers are the target of a vendetta. Five-O must discover why they were a target and stop any further violence.

A politician trying for the Senate is weakened by the murder of the man who is blackmailing him.

The series concludes with the final showdown between McGarrett and Wo Fat. Three scientists have gone missing. They have one thing in common: they all attended a symposium that discussed a possible space-based, laser defense system. McGarrett impersonates a fourth scientist, Dr. Elton Raintree, who attended the same gathering and is soon abducted. Wo Fat is behind it all and wants the scientists to complete their work and produce such a device.