How does someone become a composer? Klaus Huber, one of the most important composers of the second half of the 20th century, answers this question to his 12-year-old grandson with simple and vivid images. Barbara Eckle's film offers a fascinating insight into Huber's compositional thinking and also sheds light on his family background in a relaxed way, bringing him closer to the viewer on a human level. The documentary focuses on the commented rehearsal work for the chamber version of the 2002 masterpiece ''Die Seele muss vom Reittier steigen'' (The soul must come down from the mount), based on a text by the Palestinian Mahmoud Darwish. Huber's daughter Katharina Rikus sings and speaks the Arabic solo part, while the cello dialogues with its historical relative, the barytone. A complete reproduction of the work rounds off the documentation.