1934. After the uprising of the Schutzbund workers was suppressed, engineer Hans Müller left Austria and emigrated to the USSR. In Russia, Hans finds his love. His relationship with Galina is not easy. Her son San'ka painfully experiences the arrival of a stranger in the house. But, in the end, Hans wins the boy's trust. When the Franco rebellion begins in Spain, Hans volunteers to fight in the ranks of the International Brigade. And after the liberation of Vienna, he returns to his homeland.—Tango Papa