A well-to-do professor working in Moscow strikes up an unlikely friendship with a stray dog and attempts a scientific first by transplanting the testicles and pituitary gland of a recently deceased man into the dog.

With a wild, but alarmingly human animal on the loose, the professor's previously respectable life becomes a nightmare beyond his imagination. A suberp satirical novel, it is also a sharp and pointed criticism of Soviet society, especially the new rich that arose after the Bolshevik revolution.