1947: the Russians have uranium extracted from the newly founded SAG Wismut mine in the Ore Mountains. Among the miners is Kurt, who has become an enthusiastic communist while a prisoner of war in Russia and therefore hates his father, a convinced Nazi. Kurt falls in love with Lydia. The daughter of Soviet Major Burski was actually supposed to spy on him, but soon returns his love. However, this is not under a good star. A mining accident is in the offing.