It's Manny's first day at school and he wants to wear a poncho to school. Jay talks him out of it using jokes, and Gloria is upset. She wants to interrupt their day at the spa to bring him in his poncho until she discovers the kid also wants to play the flute to his new classmates. She makes Jay break the flute and they head home. She doesn't want her kid to die a virgin after all.
With the kids gone for the first day at school, Phil takes off the day to spend it with Claire thinking the housewife will need the company. She gets annoyed when he wants to tag along for her run and claims he won't be able to keep up to get her alone time. Phil takes this as a challenge and prepares for a race that afternoon. In the end, Claire lets Phil win because the first day is tough on all her children... especially the one she married. Her words, not ours.
Meanwhile, Mitchell and Cameron freak out when Mitchell bumps Lily's head against a door frame while dancing with her. They rush her to the doctor, who informs them Lily is okay, babies were built for new parents. On the way out, they accidentally lock Lily in the backseat, but OnStar comes to the rescue and unlocks the doors.