After a hectic Halloween night of lost Spider Monkeys and warring cat gangs, the operatives of the Three Dog Detective Agency are in need of a restful night, especially their leader, Levi. No sooner has Levi settled into the pages of his favorite Sherlock Holmes book, however, before he is confronted by a mystery that quickly becomes a life and death situation. And it's a harrowing mystery he must investigate on his own...with a little help from the Great Detective, of course.