The Young Go Wild.

High school student Fabian König is kicked out of school and starts a gang that specializes in theft. He falls in love with the orphan girl Ulla, but she rejects him when she finds out how he spends his time. When the pimp Horst tries to rape Ulla, she is rescued by Fabian. Shortly afterwards, Horst's body is found and Fabian is convicted of the murder due to the false testimony of a witness. In prison, he comes to trust the prison doctor Dr. Knittel, who believes him and is able to unmask the real culprit.