DM and Penfold have just retrieved a stolen secret fuel sample from Field Marchall Rommole. On their way back, the Mark 5 gets hit by an electric storm, Penfold is struck dumb and the two of them are shot into a distant future where Britain cats are the dominant species. Worse still, a distant relative of Baron Greenback rules the cats under the name of 'Big Leo'.—The TV Archaeologist