During the war, the Germans exported breeding horses from Russia, among which was Ermakov’s favorite. After the war, he managed to find her and return her to Russia, but the tribal certificate was lost. And now, forty years later, the granddaughter of this horse - the magnificent race mare Secunda - is being sold for pennies at an international auction to a certain Baron von Ritter. Ermakov guesses about the true owner of the “lost” document and, in the end, returns it to himself.