Jiří Trnka was one of the greatest Czech artists of the 20th century and one of the founders of puppet animation. His poetic and imaginative work contrasts sharply with the dark era of the 1950s in communist Czechoslovakia. His work was used by the regime as proof that communist society could provide artists with excellent conditions for creation. The ideological struggle between the West and the East did not avoid children and their stories.

The documentary Jiří Trnka: A Long Lost Friend is told through the eyes of a filmmaker who traces the fate of Jiří Trnka, the author of the films of his childhood, which he saw in France as a child in a working-class cinema that screened Eastern European animation. During his travels to Czechoslovakia in later years, he met Tereza Brdečková and together they try to find an answer to the question of who Jiří Trnka was. They discuss his difficult beginnings, his influence on the Czech puppetry tradition, and his almost fatefully accidental invitation to head an animation studio. They trace his journey to worldwide success in the dark 1950s to his conflict with the communist regime at the end of his life.