After reading Higgins' invitation, Magnum questions if Higgins is Robin Masters. This is the first time Magnum does this and will continue to do so throughout the rest of the series run.
The Lazarus Ranch is the same location used as the O'Shea Ranch in Season 8, The Love That Lies (1987). Coincidentally, both episodes feature a story-line revolving around Carol Baldwin (Kathleen Lloyd).
This is the second of three Magnum, P.I. (1980) episodes which David Hemmings directed--Fragments (1984), Compulsion (1985) and Let Me Hear the Music (1985). He also was a cast member in the middle episode (Compulsion).