Air date - Tue 12th of September 1972
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.
Air date - Tue 19th of September 1972
When two of a egotistical racing driver's support staff are murdered, suspicions of sabotage fall upon his attractive girlfriend.
Air date - Tue 26th of September 1972
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.
Air date - Tue 3rd of October 1972
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.
Air date - Tue 10th of October 1972
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.
Air date - Tue 17th of October 1972
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.
Air date - Tue 24th of October 1972
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.
Air date - Tue 31st of October 1972
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.
Air date - Tue 14th of November 1972
McGarrett becomes involved with the Vashon mafioso family after the youngest member, Chris, is implicated in a daring raid on a hotel.
Air date - Tue 21st of November 1972
McGarrett must contend with Honore Vashon, who wants revenge for his son's death.
Air date - Tue 28th of November 1972
Dominick Vashon, the patriarch of the clan, makes his attempt to bring down McGarrett and Five-O.
Air date - Tue 5th of December 1972
When McGarrett arrests a group of vigilante nationalists, hidden bombs at the courthouse threaten to destabilise the islands.
Air date - Tue 19th of December 1972
A husband and wife team of scam merchants get caught between some of Hawaii's most powerful mobs.
Air date - Tue 2nd of January 1973
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.
Air date - Tue 9th of January 1973
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.
Air date - Tue 16th of January 1973
A crazed electronics wizard threatens the lives of a psychiatrist and his patients by using electronic devices and gadgets.
Air date - Tue 23rd of January 1973
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?
Air date - Tue 30th of January 1973
A senior partner in a stock exchange firm comes up with a foolproof plan to rob the Honolulu Stock Exchange.
Air date - Tue 6th of February 1973
McGarrett and company must break through a tissue of lies in order to protect a Russian defector from being killed.
Air date - Tue 13th of February 1973
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.
Air date - Tue 20th of February 1973
A travel agent who operates gambling trips is killed in order to send a warning to others that the syndicates will not tolerate competition.
Air date - Tue 27th of February 1973
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.
Air date - Tue 6th of March 1973
A burglary at the home of a well known island family sets off a series of events that ends in murder.
Air date - Tue 13th of March 1973
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.