Plum Spooky
Plum Spooky (2009) is a novel by Janet Evanovich starring the fictional character Stephanie Plum.
One of four holiday novellas in the series (now referred to by the publisher as "Between-the-Numbers Novels") that star the Unmentionable Diesel. Plum Spooky is much more ambitious than the other "Betweens" in that the nefarious activities uncovered have world-wide implications, and the plotting and action are more similar to a Plum "Numbers" novel.
Plum Spooky features Carl, the monkey with an attitude problem, and introduces the villain, Gerwulf (Wulf) Grimoire, Diesel's evil cousin.
After Plum Spooky, Evanovich spun off Diesel and the villain Grimoire into the Wicked series, starting with Wicked Appetite (2010) and continuing with Wicked Business (2012).