It\'s hard enough for Scooby and the gang to crack the mystery of a Dickensian Yuletide ghost...but it\'s harder with \'help\' from Mystery, Inc.\'s newest member: Harley Quinn! Harley\'s decided to try a new career as a ghost-busting detective-and when she swings that giant mallet, nobody\'s going to tell her \'no.\' But the gang doesn\'t suspect the real reason for Harley\'s relocation: She\'s on the run after a \'lover\'s spat\' with The Joker-and Mistah J wants her back!(W) Sholly Fisch (A/CA) Dario Brizuela\"