A classic Ngaio Marsh novel reissued. ENTER A MURDERER The crime scene was the stage of the Unicorn Theatre, when prop gun fired a very real bullet; the victim was an actor clawing his way to stardom using bribery instead of talent; and the suspects included two unwilling girlfriends and several relieved blackmail victims. The stage is set for one of Roderick Alleyn's most baffling cases…