Poland in 1946. A gang of 'Thunder' is committing violent robberies and murders and terrorizes the population of a large territory, consistently moving away from retribution. Captain Morava gets to knoa that 'Thunder' has a well-informed informant between his pursuers. The captain comes up with a cunning plan.
Karwowski, son of a pre-war colonel, is transferred from the West to Poland with the task of assembling a spy and diversion network. The task seems to be easy. However, after landing in Poland, it turns out that nobody wants to cooperate with him. Karwowski's "100% reliable" contacts with potential collaborators turn out to be completely outdated.
