It’s officially the end of the Sheldon Cooper era at CBS. After a combined 19 seasons and 420 episodes between The Big Bang Theory and Young Sheldon, the genius is no more. But CBS isn’t letting their highest-rated comedy franchise go so easily. This fall, the net will launch Georgie & Mandy’s First Marriage revolving around the eldest Cooper child. It’s a sequel to a prequel, yet is still itself a prequel. Make sense?