Raymond Parmel, a murderous former soldier, claims to have the remains of Peking Man, the fossilized bones of prehistoric humans found in China in the 1930s that disappeared shortly after the attack on Pearl Harbor in 1941. McGarrett must deal both with him and with a professor who represents the government of the People's Republic of China, which wants to recover the bones as a Chinese national treasure, and doesn't care whether Parmel is captured or not.
After killing a drug dealer who stiffed her, an impoverished psychotic woman asks her friends (who are in similar dire financial straits) to go with her on a scheme to rob tour buses for the valuables the tourists are carrying. The other two women agree, but things go south when the leader, Dina, starts using her big .45 automatic far too many times.
A hit man takes a shot at a man on a boat arriving in Honolulu harbor from a distance of about a half mile, using an old tower on Sand Island as his sniper's nest. An apparently homeless boy named Moki, however, witnesses the hit man as he fires the shot. The hit man gives chase, but Moki escapes. McGarrett manages to locate the boy and sends him to juvenile detention for his own protection, but he does not figure on the intervention of Frances Chai, a crusading deputy public defender.
Colin Nichols is a vicious British soldier of fortune, looking for a missing art object that is part of a set of ancient Hindu figurines known as the "Ring of Life." He tortures and kills one man in Hawaii in pursuit of the missing piece, hoping to claim a $1 million reward from the government of India for return of the stolen item. The murder brings McGarrett and Five-O into the case, but it turns out that Nichols is not the only one after the missing artifact or the reward.
Mike (Richard Hatch) carries a torch for Glynis (Gretchen Corbett) and concocts an elaborate scheme, involving multiple murders, so that they can be together. To catch the killer the Five-O team must analyze a surreal painting a psychiatrist made of Mike's disturbed mental state.
A skydiver and a private pilot team up to retrieve heroin shipments from the ocean and then airdrop them onto Oahu, in order to evade a recent tightening against drug smuggling into Hawaii. McGarrett and Five-O learn that there is something afoot when an addict who knows of their plan is gunned down in a telephone booth as he tries to warn Five-O.
A paranoid Korean War veteran, thinking a policeman is about to arrest him for a crime he didn't commit, grabs the officer's gun and shoots him. More cops appear, so the vet pulls the wounded officer's ammunition belt free and runs into an apartment occupied by a teenage girl, locking himself and the girl inside. McGarrett and HPD's SWAT team arrive at the same time, and the leader of the SWAT team wants to blast his way into the apartment and take down the gunman, who blazes away at targets all over the place. Because somehow the gunman hasn't killed anybody yet, and...
One of the better of far too many TV-series episodes advocating gun control, as four owners of a single Saturday Night Special automatic use it for death and destruction (including, in one case, a child shooting himself). Ramon Bieri, the lone credited "guest star" imported from the mainland, plays a postal worker who finds the weapon and goes postal with the gun on his wife and her lover. Stuntman and many-time bit player Beau Van Den Ecker has the second-largest role as a thug who uses the weapon in the last 15 minutes of the show to rob and shoot up convenience ...
A criminal syndicate has stolen 6,000 airline, cruise and attraction tickets and is now shoving them down the throats of travel agencies, forcing them to pay for them and then "eat" them to avoid taking the blame for stealing stolen merchandise. To make sure the travel agencies stay in line, one of them is bombed, killing three people. An undercover agent from the mainland helps Five-O infiltrate the gang. The only chance you will get to see similarly-named actors Jack Hogan (who gets top billing because he was a regular on "Sierra" at the time of filming; he plays ...
The U.S. Navy's top "spy catcher" is killed by a powerful letter bomb while in Honolulu. Five-O's Steve McGarrett, while serving a two-week hitch in the Navy Reserves, is called upon to investigate the slaying. The death is tied to a security leak within Naval Intelligence and it turns out that Wo Fat is its mastermind.
Mobster Charlie Bombay, an old foe of McGarrett's, escapes from prison, thanks to a bribed guard. But Bombay's confederates tip Five-O to Bombay's whereabouts before Charlie can flee Hawaii. McGarrett arrests Bombay in Hilo, thanks to the tip and wants to take the criminal back to prison personally. But the small police airplane containing McGarrett and Bombay crashes because of turbulent weather. The pilot is killed in the crash and Bombay overpowers an injured McGarrett.
Susan has been having an affair with a man involved in skimming the gambling take from some Las Vegas casinos and has been acting as a courier, taking the money to Hawaii. She decides to get out and, in a fight, with her boyfriend, shoots him. She thinks she killed him. What she doesn't know is that a hit man entered the boyfriend's apartment minutes later and killed the man. Now, Susan is on the run -- not knowing the hitman is about to make her his next target. Five-O tries to find Susan before it's too late.
A man arrives at Honolulu International Airport and is taken to the hospital after being struck by a car. Upon reviving, he checks the bag he was carrying and, being unable to find something in it, takes a cyanide capsule he had hidden in his jacket pocket and dies. The hospital had taken the object and put in a safe with his other valuables. Five-O discovers the object is part of a small surface-to-air missile. McGarrett recruits a police officer who can pass for the man and he will make attempt to make contact with those the dead man was going to meet. Five-O ...
After being denied parole from prison, crime lord Honore Vashon comes up with a twisted scheme to exact revenge on McGarrett for the deaths of his son Chris and his father Dominick by taking a group of prison officials hostage. He then exchanges the officials for McGarrett and then places McGarrett on a mock trial for the alleged crimes he committed against the Vaschon family. Can Danny and the rest of the Five-O team save Steve before Vaschon sentences McGarrett?
A spy ring targets a U.S. missile project headed by Dr. Grant Ormsbee, a headstrong scientist. The bait is an agent posing as an Asian scientist Orsmbee had met 12 years previously and who had maintained correspondence with Ormsbee. McGarrett clashes with Ormsbee initially when the scientist refuses to cooperate with Five-O's investigation of the death of a member of the spy ring, who has been sacrificed as part of the group's complicated plot. Ormsbee eventually agrees to play Judas Goat himself as Five-O and Naval Intelligence attempt to smash the spy ring.
Singer Chelsea Merriman witnesses Koko Apaleka striking his girlfriend, causing her to fall from a high-rise balcony. Chelsea initially tries not to become involved, resisting McGarrett's attempts to get her to testify. But after Koko tries to intimate Chelsea by sending a doll with a broken head to Chelsea's daughter on the Mainland, the singer decides to cooperate with the authorities. Now, McGarrett & Co. must protect Chelsea from Koko's attempts to have her killed.
Dan Williams welcomes his Aunt Clara to Hawaii for a visit. On the flight over, she got to know Edgar Miller, an elderly man on the same flight. Once he checks into his hotel room, Miller encounters two attackers but not before he makes a telephone call to Clara. Five-O's Duke, investigating Clara's call, is initially taken in by an impostor pretending to be Miller. But Five-O, after the real Miller's body is discovered, begins an investigation. McGarrett & Co. utilize Clara as part of a con to bring the conspirators to justice.
Morwood, a high school official, has organized a smuggling ring. His confederates are forced to toss a drug shipment overboard as the Coast Guard is ready to close in. Morwood's group knows the approximate position but can't make a move because Five-O and the authorities have the heat on. But when Morwood spots a mini-submarine he gets the idea the the vessel could snatch the drugs out from under the nose of the police.
Mendoza is the manager of a string of warehouses along Hawaii's waterfront. He, his daughter and a group of hired thugs knock over the warehouses one by one and steal their contents. A robbery goes horribly wrong and ends in the death of an HPD officer. A robber, shot in the stomach, manages to get away with the manager's daughter in tow. They park their truck in a deserted area and try to hide. What they don't know is that their stolen cargo is a vat of highly volatile chemicals which will explode under the tropical sun in a matter of hours.
Egotistical author Travis Marshall discovers the unmarked grave of heir Brian Henderson. Marshall is promoting his find to the media, much to the annoyance of McGarrett & Co., who have re-opened an investigation. Brian Marshall has been missing for seven years. Five-O has to reconstruct what happened to the heir, with no help from Marshall or Agatha Henderson, the wealthy grandmother of the dead man. The case turns out to be an elaborate jigsaw puzzle for McGarrett, which is further complicated when Marshall turns up dead.
Three college football players, one the son of a powerful senator, rape a waitress. The senator sends his "fixer," a lawyer working for him, to take care of the situation. The fixer finds a petty criminal willing to be a patsy in return for $5,000 and a guarantee that charges won't be pressed against him. Five-O tries to find out what really happened. Meanwhile, the victim moves to take matters into her own hands.
August March, a seemingly respectable businessman who is also an art collector, has been running a smuggling ring of Asian art. When he discovers McGarrett is also a collector of small Asian sculptures, March arranges for a stolen piece of art from Japan to be substituted for McGarrett's collection, which is about to go on display in a Honolulu museum. March sees this an opportunity to frame the lawman who could smash his operation. But McGarrett, despite all odds, moves to trap his opponent.
Deadly liquefied nerve gas is stolen. Five-O investigates the theft; the substance can kill a person if only a drop touches their skin and a small quantity can cause mass casualties. But the thief isn't a terrorist or master criminal. It's a young man seek revenge against Dan Williams. Danno investigated the young man's father, a corrupt police officer. The young man concocts a frame for Williams that Five-O will find difficult to prove false.