When Higgins asks his help in finding Robin's latest manuscript after it is stolen, Magnum gets some unexpected help in the case when St. Louis gumshoe Luther H. Gillis arrives unannounced on vacation. They set about trying to work out who is so desperate to get hold of the manuscript that they are willing to resort to attempting to kill Higgins and drugging Zeus and Apollo to get it, in scenes reminiscent of those portrayed in the stolen book.

As Rick's wedding looms ever closer, Magnum continues his surveillance on Linda to try and catch the psychopathic killer who is stalking her. T.C. faces a reconciliation with his estranged wife. And Magnum gets some surprising news about his theory that Higgins is really Robin Masters, as well as the true fate of Lily.