Contemporary filmmaker Hannah Rothschild tries to uncover the real story behind her great aunt's sudden disappearance. In 1951 the beautiful married mother of five left home and went to New York in search of the man who wrote 'Round Midnight. She found him and this is the extraordinary account of what happened next. A journey that took her from Harlem to Hell and back again. She went to prison for him and gave up everything familiar. But why? Helen Mirren reads Pannonica's words and Sonny Rollins, Quincy Jones, TS Monk junior, Roy Haynes, Curtis Fuller, The Duchess of Devonshire and other luminaries tell their side of the story. This film is the result of a ten year search to solve the puzzle of Pannonica.