An onscreen title describes this documentary by James and Maureen Tusty as “the story of how culture saved a nation,” as if the defiant singing of Estonian anthems at the Baltic country’s annual music festival compelled Soviet soldiers to lay down their guns and go home. That’s not exactly how it went, but the movie does show how the forces of nationalism withstood and finally turned back the tide of Soviet communism. The Tustys present a clear and concise history from the 1939 Russo-German pact, which gave Estonia to the USSR, through Stalin’s immigrants, through Gorbachev’s glasnost policies, which let the nationalist genie out of the bottle. The pace quickens considerably with the onset of the organized independence movement, which culminated in a tense but relatively nonviolent endgame as the USSR fractured in 1991. 97 min.