The cover version has always been a staple of the pop charts. Yet it's often been viewed as the poor relation of writing your own songs. This film challenges and overturns that misconception by celebrating an exciting, underrated musical form that has the power to make or break an artist's career. Whether as tribute, reinterpretation or as an act of subversion, the extraordinary alchemy involved in covering a record can create a new, defining version - in some cases, even more original than the original.