When Higgins unwittingly causes Magnum to wipe an expensive computer game loaned from T.C., and Thomas accidentally erases a chunk of Higgins' memoirs stored on the computer, a feud breaks out between the pair. Magnum is trying to break a major, crooked gambling ring that is operating on the islands, but it is none too easy while in the middle of the falling out with Higgins, which starts out with each trying to out-do the other with "eye for an eye" practical jokes, and quickly develops into a particularly bitter battle of wills. Magnum accuses Higgins of being Mr. Robin Masters.
- 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