A beautiful thief (Joanne Linville) posing as a socialite schemes to steal a Hawaiian royal jewel; guest George Gaynes.

The Five-0 team has 12 hours to learn where a scientist (Ed Flanders) hid a vial of deadly mutant microbes.

A scientist (Ed Flanders) vanishes after discovering a deadly biological mutation.

A renowned research scientist, conned into believing he shot and killed a man, disappears from his important government assignment.

A grief-stricken policeman takes the law into his own hands after his wife is murdered; guests Tom Skerritt, Sam Melville.

One of McGarrett's most trusted investigators is accused of accepting a bribe from a major narcotics dealer; guest Martin Sheen.

An angry man seeks revenge after a crooked poker game costs the life of his honeymooning brother; guests Jack Soo, John Colicos.

Someone is deliberately tormenting a disturbed Vietnam veteran guilty of kidnapping.

McGarrett clashes with the Navy when he tries to bring in a suspect in a shore patrolman's murder; guest Christopher Walken.

The girlfriend of a fitness guru dies while attempting a hanging-type exercise.

An order from the governor is necessary to stop blinded McGarrett from pursuing the assailant responsible for his loss of sight.

An adversary (William Windom) of McGarrett's pulls off the perfect heist in front of Five-0; guest Jackie Coogan.

A Texas heiress (Beverlee McKinsey) pits a beachboy against a playboy in a bizarre card game in which their lives are the stakes.

After his kidnapped son escapes, a wealthy man demands McGarrett recover the $300,000 ransom he paid to the boy's abductors.

McGarrett must protect a dictator whose jet made a forced emergency landing in Hawaii; guest Paul Stevens.

McGarrett's investigation of a former mobster implicates a state committee head; guests James Gregory, Keye Luke.

A woman, the only witness to a murder by a wanted Hawaiian crime figure, asks McGarrett to come to Singapore and escort her back.

A prank turns serious when university students who stole the cherished robe of King Kamehameha decide not to bring it back.

A foreign agent (Theodore Bikel) threatens germ warfare and the end of Hawaii's sugar industry; guests Philip Ahn, Soon-Teck Oh.

A radical Maoist attending college in Hawaii is found dead as evidence links him with a Chinese intelligence operation.

Members of a small, foreign guerrilla force burglarize an armory to steal weapons for a revolution in their country.

A small-town salesman witnesses a prostitute's murder but refuses to testify; guest Elaine Joyce. Directed by Nicholas Colasanto.

Agents of the People's Republic of China use a false tidal-wave forecast to mask the kidnapping of a scientist (Will Geer).

A deranged Japanese man returns to Hawaii to complete his mission to destroy Pearl Harbor; guest Mark Lenard.

Three wives of men killed in Vietnam die after collecting their husbands' G.I. insurance; guests Harry Guardino, Loretta Swit.