The Knight of Darkness hunts hidden crimelords in two thrilling mysteries by Walter B. Gibson. First, the only clue to the deadly crime wave engulfing Manhattan is a single wireless message typed out in Morse Code: 'Q.' Then, a brilliant mathematician invents a system to chart future crimes. Can The Shadow use the 'Formula for Crime' to solve the mysterious 'X' and unmask a criminal mastermind? Plus, an ultra-rare classic from the Golden Age of Comics!