Physics professor Jacob Hicks is an innocent bystander, but that doesn't keep him from once again getting in the middle of a mystery when an unobtrusive shop owner is murdered. When Jacob's imminent breakthrough on his crime-solving computer turns out to be a bust, his sidekick, Emily Dawson, thinks some amateur sleuthing might be a good distraction. Meanwhile, Paddy the Rat and his pal Vinnie hope for a quiet holiday in the sewers...