Magnum returns from a case to find that Higgins' old Army commander is staying on the Masters estate, under tight security, until some I.R.A. members he helped capture are tried. Two secret intelligence agents hire Magnum to protect the brigadier and foil assassins out to kill him before the terrorists' trial, but the “need to know” basis the agents insist on operating by only serves to complicate matters for Magnum.

When a beautiful model-actress is killed by a shotgun blast in a scenario closely resembling a scene from the script of an upcoming film, it is seemingly suicide. Magnum is hired by her former producer and lover to investigate any other men that she may have been seeing before her death.

Higgins volunteers Magnum's services to guard a wealthy socialite's quarantined dog after the attempted dognapping of the canine. Sir Algernon Farnsworth soon finds himself to be the most wanted dog in Hawaii when his former owner, aging gangster Victor DiGiorgio, needs to get him back.

Magnum is hired by a Supreme Court nominee to find the woman he married on the eve of the raid on Pearl Harbor.

T.C. makes a late-night flight to land on a tanker, but on the journey back he is cornered and arrested by the Coast Guard for transporting drugs. Magnum and Rick are certain of their friend's innocence, but are shocked when he intends to accept the charges and refuses their help.

A woman hires Magnum to protect Norman, who is facing kidnap unless she pays a ransom; but the case has some unexpected twists.

An aloof, beautiful girl, a Sumo wrestler, and a little person spell trouble and intrigue.

A team of private investigators fly to Hawaii to recover a valuable and deadly native artifact, and find themselves in conflict with private investigator Thomas Magnum, Higgins, and a beautiful (but larcenous) socialite.

The crossover continues on Simon & Simon S02E01 Emeralds Are Not a Girl's Best Friend (II).