The film tells the story of a young village girl who leaves home for a factory during World War II, lured by promises of easy money and a good life. Soon after arriving at the factory, however, she realizes that all the promises were lies, but Danka will not give in to discouragement. After the liberation of Bulgaria by the Soviet Army, she happily went to work with the other workers in the factory, which now belonged to the people.

Constantinople, 1883. During an outing to the Black Island Edith, the adopted daughter of the French ambassador, is saved by Kalin the Eagle. She learns that he is a Bulgarian revolutionary from the April Uprising of 1876. With her help Kalin the Eagle escapes and returns to the liberated Bulgaria, where he is drawn to the socialist movement. Edith finds out that Kalin is in fact her father, and sets out in search of him. Kalin the Eagle is notable as the first movie made by the nationalized film industry after World War II in the newly formed People's Republic of Bulgaria.