Magnum is hired to protect a British Brigadier who is hunted by the IRA.
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.
- Tom Selleck as Thomas Sullivan Magnum IV
- John Hillerman as Jonathan Quayle Higgins III
- Roger E. Mosley as Theodore "T.C." Calvin
- Larry Manetti as Rick Wright
- Remi Abellira as Mok
- Robin Dearden as Mandy, the Flight Attendant
- Edward Grover as Hooker, the CIA Agent (credited as Ed Grover)
- Richard Johnson as Brigadier General Alistair Ffolkes, Royal Army
- Mariko Van Kampen as Suzie, the Flight Attendant
- Reri Tava Jobe as Hostess (credited as Reri Tava)
- Gene Hamilton as CIA Agent Dobey (credited as Eugene Hamilton)
- David O'Malley as Dirk (credited as David P. O'Malley)
- The uncommon surname of character Brig. Gen. Alistair Ffolkes is the same as the character Rufus Excalibur ffolkes, played by Roger Moore in the movie North Sea Hijack (1980) that opened in the US on 18 April 1980 under the name "ffolkes".
- Both John Hillerman and Richard Johnson played Dr. John Watson within a year of each other. Hillerman (an American) with Edward Woodward (an Englishman_ as Holmes and Johnson (an Englishman) with Charlton Heston (an American) as Holmes.
- Rick Wright: Taste this. The South Africans even go nuts for it.
- Mandy: You must be the private eye Robin told us about.
- Magnum: I prefer to be called private investigator.
- Higgins: You prefer to be called, period.
- Magnum: I don't whip off my glasses and rush into a phone booth.
- Higgins: Not if it's a pay phone anyway.
- Brig. Ffolkes: I thought we disposed of our man last night, Magnum. I suppose we missed somebody.
- Magnum: It was the girl, Brigadier, and your men didn't miss her.