Rowf, a Labrador-Mix, and Snitter, a Smooth Fox Terrier, are two of many dogs used for experimental purposes at an animal research facility in the Lake District of north-western England. Snitter has had his brain experimented upon while Rowf has been drowned and resuscitated repeatedly. One evening, Snitter squeezes under the netting of his cage and into Rowf's, where they discover his cage is unlatched. They explore the facility in order to escape until they sneak into the incinerator, where they are nearly killed before finally escaping.