The distant future...Continuation of the adventures of Imperial Security Service agent Thomas Brain! Brain is sent to a new duty station - to a planet that intelligent alien lizards are trying to capture. Cunning creatures take the form of creatures belonging to various cosmic races and are going to push galactic humanity away from the planets they have conquered. Brain is arrogantly greeted at the military special unit, despite the fact that he arrived there by order of his superiors. He, an elite expert on intelligent lizards, is registered as a reservist and assigned a tiny salary. It is not surprising that when a crime boss invites Brain to cooperate, he begins to wonder: is everything purely in the service?..