September 12, 1972 8:00 pm
A local thug, Piro Manoa, is trying to create the impression of corruption in the Five-O force, and Duke is implicated in a murder. McGarrett and the team, with new recruit Ben Kokua, must save Duke's position and work out the plot of the organisation behind the false accusations.
September 19, 1972 8:00 pm
When two of a egotistical racing driver's support staff are murdered, suspicions of sabotage fall upon his attractive girlfriend.
September 26, 1972 8:00 pm
A private investigator, Sam Tolliver, arrives from Texas to help an old friend who is being blackmailed and is at risk of being killed if he doesn't pay up, but he ends up wanting to become part of the blackmail operation.
October 3, 1972 8:00 pm
Danno shoots an apparently armed teenager but finds that he was mistaken, and public opinion and the teen's brother turn against him. McGarrett must act to defuse the potentially explosive situation.
October 10, 1972 8:00 pm
Wo Fat is suspected of being behind the theft of a mobile ICBM device, and McGarrett with other top officials must stop him selling it off to the highest bidder.
October 17, 1972 8:00 pm
Army computer technician Jack Gulley kidnaps a scientist and then uses a planned heist by three accomplices on a military base to divert Five-O's attention from his sale of the scientist to the highest bidder.
October 24, 1972 8:00 pm
A doctor tracking venereal disease is murdered, and Five-O must track the series of encounters to find out who is a carrier. Their investigation is made doubly important by the murder of a young woman who is close to a upcoming politician. He seems a likely suspect but McGarrett suspects a deeper plot.
October 31, 1972 8:00 pm
Danno is found in the back of a truck, dazed and confused, and McGarrett and the others must help him piece together how he came to be in that situation.
November 14, 1972 8:00 pm
McGarrett becomes involved with the Vashon mafioso family after the youngest member, Chris, is implicated in a daring raid on a hotel.
November 21, 1972 8:00 pm
McGarrett must contend with Honore Vashon, who wants revenge for his son's death.
November 28, 1972 8:00 pm
Dominick Vashon, the patriarch of the clan, makes his attempt to bring down McGarrett and Five-O.
December 5, 1972 8:00 pm
When McGarrett arrests a group of vigilante nationalists, hidden bombs at the courthouse threaten to destabilise the islands.
December 19, 1972 8:00 pm
A husband and wife team of scam merchants get caught between some of Hawaii's most powerful mobs.
January 2, 1973 8:00 pm
Two drifters, Gar and Nina, steal children and sell them on to a mainland adoption agency in order to raise the cash to buy a boat and go cruising.
January 9, 1973 8:00 pm
McGarrett agrees to let Toni, a tough female convict, get married and have a honeymoon in protective custody as long as she will testify against a local hood.
January 16, 1973 8:00 pm
A crazed electronics wizard threatens the lives of a psychiatrist and his patients by using electronic devices and gadgets.
January 23, 1973 8:00 pm
Five-O has a suspect for a murder, but they have one problem. How can the suspect have been in two places at the same time?
January 30, 1973 8:00 pm
A senior partner in a stock exchange firm comes up with a foolproof plan to rob the Honolulu Stock Exchange.
February 6, 1973 8:00 pm
McGarrett and company must break through a tissue of lies in order to protect a Russian defector from being killed.
February 13, 1973 8:00 pm
Two simple criminals kidnap a young girl, and hide out in a bunker at Diamond Head. McGarrett must unravel the reason why they are there and get the girl safely away from them.
February 20, 1973 8:00 pm
A travel agent who operates gambling trips is killed in order to send a warning to others that the syndicates will not tolerate competition.
February 27, 1973 8:00 pm
Chin Ho must face the fact that his daughter, Alia, is in love with the son of a local criminal under investigation, and that she plans to get married to him.
March 6, 1973 8:00 pm
A burglary at the home of a well known island family sets off a series of events that ends in murder.
March 13, 1973 8:00 pm
A single person is holding out in a Five-O trial, and McGarrett and the team have to find out who is stalling and why they are doing it.