Topher"s amazing cat, Ka, has time-travelled again; she has left him the clue: CAppeLLis Following her, Topher finds himself in Victorian London where disease is rife and the Thames is clogged with stinking sewage! Topher discovers a plot to kill Joseph Bazalgette, the man who is trying to save the city. Determined to foil it, Topher must first escape from an arch-criminal and his den of thieves. This is the sixth adventure of the "Time-Travelling Cat".