McGarrett sends an undercover agent into a rehabilitation home for juvenile offenders to find out who is behind the theft of gold from dental supply warehouses.

Ben Tanaka, a well-known ecologist, seems to be behind the kidnapping of a wealthy land developer's wife, but all is not as it seems and a conspiracy gradually reveals itself.

The son of a Japanese businessman is kidnapped and held in a capsule underwater until a $1.5 million dollar ransom is paid...

Criminals threaten to use a special type of moth to wipe out the sugar cane on Hawaii and destroy the industry.

When an airline stewardess and a hang-gliding instructor are murdered, Five-O must find the killers.

A crooked contractor and a buildings inspector are under suspicion after the new Global Trade Center in Honolulu goes up in flames.

A clear cut murder case against an island mobster is derailed due to McGarrett.

When an elderly importer who was a World War II Japanese spy is killed, Five-O seeks his killer.

A disturbed young man steals nerve gas to use against a visiting royal family as revenge for the death of his father.

When McGarrett suspects respected businessman and collector August March as working in a smuggling operation, he decides to set a trap to catch him in the act.

Three boys commit a gang rape on a waitress, but one is the son of a Senator and the crime is covered up...

A writer who specializes in solving mysteries uncovers the body in a seven year old case, but it raises more questions than it answers...

When Five-O fail to prevent a series of thefts at dockside warehouses, an influential owner creates trouble for McGarrett.

A vice-principal enlists the help of his students and a submarine to smuggle drugs.

Danno's Aunt Clara becomes acquainted with a man on the plane to Honolulu, but becomes concerned about him afterwards. Dan, Steve and the others ignore her at first, but then the man turns up dead...

When a singer witnesses a murder committed by a racketeer, Five-O has to protect her until she can give evidence, but this is not an easy job...

McGarrett meets his match in Dr. Grant Ormsbee, a grumpy and aggravating scientist who is sheltering a suspected Chinese defector.

McGarrett offers himself as a hostage exchange, but is then put on 'trial' by Honore Vashon.

A road accident starts the trail towards a plot to use SAM missiles to bring down a VIP jet plane.

Five-O must find a female courier who witnessed a murder before a hitman can...

A British agent, Harry Wells, arrives in Hawaii in pursuit of a turncoat, but not all is what it seems for Five-O...

McGarrett must again face mobster Charlie Bombay when a plane carrying them to Honolulu crashes in the forests.

McGarrett must try his utmost to foil Wo Fat's plans which include hostages and brainwashing.

When a letter bomb kills a Naval Officer whilst McGarrett is on Navy Duty, he is called upon to investigate and uncovers a plot involving an old nemesis...