Theatrical "angel" (and former gangster!) Frank Brooks (Stacy Harris) is charged with the murder of playwright Ernest Royce (Jerome Cowan), who has been killed in the same manner as the main character in one of his unproduced plays. It turns out that Royce has based his play on the real-life murder of underworld figure Rick Valponi back in 1947. In order to clear Brooks in court, Perry Mason (Raymond Burr) must locate the "lost last act" of Royce's play, which may not only solve the present crime but also the one that occurred 22 years earlier. ~ Hal Erickson, All Movie Guide