Pete Kelly's Blues (1955)

In 1927 Kansas City, Pete Kelly and his jazz band play nightly at a speakeasy. A local gangster starts to move in on them and when their drummer is killed Kelly gives in, although this also means taking the thug's alcoholic girl as a singer. Kelly soon realizes he has made a big mistake selling out in this way, and that rich girl Ivy is now the only decent thing in his life.