This week's "Abbott Elementary" episode is just half of the story. "Volunteers" featured the long-awaited crossover with FX's long-running "It's Always Sunny in Philadelphia," as told from the vantage point of the hit ABC sitcom.

Charlie learns to read, Dee impersonates Ben Franklin, and Frank fights raccoons. We don't quite know what's up with Dennis though.

Two comedy forces collided this week on Abbott Elementary, as the school staff welcomed the Paddy’s Pub gang from FXX’s It’s Always Sunny in Philadelphia. Did the crossover episode make the grade, though?