Looking to take a break from the monotony of being shot at, chased and general standard activity of travelling with the Doctor, he and Charley travel to Venice in the 23rd Century, where the city is preparing to sink below the water for the last time. However, once there, they encounter a dodgy cult, a proud art historian and a love sick aristocrat, as well as a rebellion by the web-footed underclass and a disappearing corpse.