After escaping from the research laboratory, the two dogs struggle to survive in the rugged and dangerous wilderness of the English Lake District. Rowf is a Labrador Retriever who has developed a deep mistrust of humans due to the painful experiments he endured in the lab, while Snitter is a terrier mix who has been subjected to brain surgery that has left him with disturbing flashes of memory and hallucinations.
As the dogs roam from place to place, they encounter a variety of human and animal characters, many of whom are poorly equipped to understand or care for them. They also become the subject of a massive manhunt, as the scientists who ran the lab fear that the dogs may be carrying a deadly disease that could infect humans.
Despite the odds against them, Rowf and Snitter maintain their bond of loyalty and support, as they face hunger, injury, and the constant threat of capture or death. The film's portrayal of the dogs' intelligence, emotion, and communication skills is strikingly realistic and empathetic, making it a powerful reminder of the ethical issues involved in animal experimentation.