Motown has finally found its groove. The Jackson Five add their bubblegum soul to the company’s more traditional sound. And albums from Motown artists rocket to the top of the Billboard charts. The record label is churning out hit record after hit record. Things at Stax Records ain’t too bad either. They’ve finally figured out how to capture some of that Motown magic, but new rules for creating music are stifling creativity. Stax musicians are pushing back. Over at Motown, songwriters clamor for more credit, creating tension between the hit writers and the check writers. The legacies of both record labels are on the line, and it's hard to know how they’ll hold on. Or, if it’s even possible.