When aliens came to extinguish the human race they needed to fill the gap in the hierarchy of animal life. The canidae were chosen as the new dominant life form, and all sub-species of canines were given a higher conciousness and the power of speech. The story focuses on Garth, a mastiff rescued from a cruel laboratory, who takes his pack on a mission to assist the aliens. Eventually he questions whether he is their help or their instrument, his predicament finally resolved in a confrontation with a greater danger than mankind.