Robin and Higgins simultaneously ask Magnum to do some investigative work, so Thomas calls on St. Louis-based gumshoe Luther H. Gillis to nail the man who's blackmailing Higgins, while Thomas goes undercover to investigate embezzlement in a bank owned by Robin's friend.

Hoping to make up for crashing the Estate's security system, Magnum has Mac fix it and challenges Ms. Krista Villaroch, a beautiful insurance security specialist, to certify it's acceptable for the Estate to host a jewelry competititon.