It depicts line by line the Greek myth of Orpheus going into the underworld to retrieve his wife from the dead. He plays his piano to persuade the Furies to release her, and his performance is so moving that they agree - with one condition, that he promise not to look at her until they're out of the underworld. But as he's leading his wife out, she pleads with him to look at her. He melts and looks and loses her forever. He took the German text and wrote it into music.
Every line has a counterpart in the German text.
Levin said he likes Beethoven's Fourth because of the drama that plays out in it. In the second movement, the Furies, portrayed by the strings, sternly warn Orpheus. Then his piano pleads, and the music goes back and forth between the piano and gradual relenting of the Furies. Amid the scripted music by Beethoven, audience members can expect to look for Levin to do some improvisation during the performance, a talent he's renowned for. It was expected of performers to do this.