Magnum returns from a case to find that Higgins' old Army commander is staying on the Masters Estate, under tight security, until some IRA 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' trail, but the ""need to know"" basis the Agents insist on operating by only serves to complicate matters for Magnum...

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, ageing gangster Victor DiGiorgio, has need to get him back. Magnum and an animal regulations officer are soon on the run with Algie from the would-be dognappers - and the fact that the officer seems to be scared of dogs doesn't exactly make matters any easier - but just why does DiGiorgio want the mutt back so badly?...