First days of September. The insurgent radio receiver intercepts the encrypted information from the Soviet radio. Courier, Captain Sergeiyev is to land at Powiśle at night. Wladek gets the job of taking the Russian. Sergeiyev gives information about planned help for the uprising - soon will be the landing of Soviet troops. Wilk has the impression that he once met a Russian officer. Slowinski orders Siwy to transport the AK archive outside Warsaw. Bronek and Michał try to unravel the code puzzle from the engineer's photos.