Shy graduate student Dmitry Neretin goes to the front to serve as a translator. After several weeks of intense fighting, a lull begins. Battalion scouts advance to the front line and return with a prisoner — a German captain who mysteriously dies at night. Neretin finds out that the captured enemy was killed right in their location. Now Dmitry will have to figure out a traitor among his associates who did not allow the prisoner to betray the secrets of the German army.