After Agatha and her friends are swindled out of $10,000 by a shady investment company, she hires Magnum to track down the crooks and retrieve their money. Meanwhile, Higgins's distant cousin arrives from England to marry the heir of a local socialite and turns out to be a punk rocker in need of a drastic makeover before she can be accepted into society.

Tyler McKinney, an old commando acquaintance, asks Magnum, Rick, and T.C. to help him rescue a buddy who is held prisoner after being captured in Chong Ker, Cambodia by Vietnamese soldiers.