Magnum P.I. S07E09 - Novel Connection

Higgins is driving visiting Pamela Bates - an old editor friend of Robin Masters' - to the Estate when someone tries to run them off the road and over a cliff. But it seems that it's not a case for Magnum, when Pamela insists on waiting for her own mainland investigator friend to arrive and look into it. Pamela's investigator friend turns out to be famous crime mystery writer Jessica Fletcher, and so both Jessica and Magnum set about investigating just who wants one of the visiting guests dead, and why.

Part 1 of 2. Part 2 is Murder She Wrote S03E08