Mister Marmee is a Victorian gentlecat, not a detective...or so he thinks. Everything changes when he takes up residence with Stephen Hanover, London's premier doctor of veterinary medicine, and his vivacious dachshund detective, Sir Happy, at their home, Hanover Place. With a nose for finding and following clues, Sir Happy soon begins to teach his feline friend the tricks of the investigative trade. Within short order, Mister Marmee finds himself whiskers-deep in one of the most perplexing and brutal crime sprees London has ever seen. Drawn into the fray by the charming but bewildered Hyrum Farley of Scotland Yard, Mister Marmee and Sir Happy follow the trail of a lifetime as they endeavor to track down a killer canine before it strikes again. From the slums of Cheapside and the dog fighting rings of the warehouse district to the sleepy manors of the British countryside, onto the very doorstep of Hanover Place itself, it's a race against the clock...and time is running out!