In Part 4 of the L/M Breakup Series, Diana and Phoebe begin their investigation into the issues that separated John and Paul and turned them against each other, the most significant of which was Allen Klein: the Demon King of the Beatles Break-up. They examine how Klein drove a wedge between Paul and John and hastened the band's demise. They also discuss what Paul McCartney describes as “the cracking of the Liberty Bell,” a hugely important moment in the journey of the Beatles.