It is July 4th and Magnum is off the coast on his surf ski when a speed boat shoots past him throwing TM into the water and the surf ski drifts away.
Thomas' annual July 4th solitude takes a turn for the worse while on his surf ski. His time spent on the water shifts between present and his childhood time when his father left for the Korean war. Rick, T.C. and Higgins each feel something is wrong, just in the nick of time.
- 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
- Gillian Dobb as Agatha Chumley
- Constance Forslund as Sandy - Rick's Companion
- Susan Blanchard as Katherine Magnum - Magnum's Mother
- R.J. Williams as Young Thomas Magnum (credited as R. J. Williams)
- Robert Pine as Lieutenant Thomas Sullivan Magnum III, USN
- Geoff Heise as Goffrey Bonner (credited as Geoffrey Heise)
- Patrick Tendo as Toby
- Norman Tang as Chinese Chef
- Dejohn Williams as Mikey
- Bud Ralston as Naval Officer (as Bud ii)
- The Hawaii Islanders were a real minor league baseball team (1961-1987) that played their home games at Aloha Stadium in Honolulu.
- At some point earlier in his life, Higgins attempted to swim across the English Channel. He almost made it, but had to give up because of a nosebleed.
- Agatha: Isn't the ocean beautiful at sunset? So soft....so peaceful...so romantic!
- Higgins: Agatha my dear...
- Agatha: Yes Johnathan?
- Higgins: I know what you're thinking.
- Agatha: You do?
- Higgins: You're trying to capture my queen by sacrificing your knight.
- Agatha: Oh Johnathan! Sometimes you a royal ass! I'm need some tea! (walks away)
- Higgins: Sometimes I think I shall never understand women...