Magnum's favorite aunt, famous playwright Phoebe Sullivan, comes to Hawaii and asks Thomas to protect her from someone trying to kill her.
- 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
- Kwan Hi Lim as Lieutenant Yoshi Tanaka