Chaos meets the classroom as the gang from It’s Always Sunny in Philadelphia lands at Abbott Elementary in the first of an unforgettable two-part crossover event! When Dee (Kaitlin Olson) tries to sell her latest "business idea" to the school, Frank (Danny DeVito) takes over the cafeteria, Mac (Rob McElhenney) and Charlie (Charlie Day) wreak havoc in the teacher’s lounge, and Dennis (Glenn Howerton) sets his sights on…let’s just say trouble. Meanwhile, Principal Ava (Janelle James) sees a chance to turn the gang's antics into a social media bonanza, leaving Janine (Quinta Brunson) to keep the school running while Jacob (Chris Perfetti) bonds with Mac over some unexpected common ground.