Glee creator Ryan Murphy’s announcement that the McKinley kids would be graduating and leaving the show at the end of this upcoming season (stated with a “isn’t-this-totes-obvs?” tone) caused a stir surprising to even Murphy himself. Gleeks are practically worked up into a lather of separation anxiety. And it makes sense: no one is excited about the prospect of Glee devoid of Rachel’s self-aggrandizing, Finn’s lumbering dance moves, Mercedes’s vocal runs, and Brittany’s non sequiturs. But his rationale is valid. Unless the show abandoned all pretense at realism (and it’s already halfway there with the rock-concert-worthy production values that accompany each performance), it’d be hard to draw out the chronology enough to allow the characters to stay at McKinley for any more seasons. But Gleeks need not worry. The original...