In 1929, music teacher Paul Leinert receives an unexpected letter from his old friend Otto Schiffmann, a young and talented composer who has moved away from Berlin after a failed marriage. The letter is an invitation for Paul to come and visit Otto in his forest cabin - and to get to know his new work, a long-awaited symphony. Taking along his wife Anna as well as his colleague Willi, the three find the cabin, but Otto is nowhere to be seen. As they go looking for him the next day, Paul notices something odd about the song of the local birds...