It's the first day of school. Luke is worried because he didn't do his summer assignment. Alex struggles to carry all her extracurricular supplies, including a cello. And Haley is miffed that her driving instructor is picking her up at school. She doesn't want her friends to think she's dating a 40-year-old who's not even cute. Makes sense.
With the kids back in school, Phil worries Claire will suffer from empty nest syndrome. He reschedules a business meeting in order to spend time with his wife. Claire is actually fine and simply wants to spend the day getting lost in a good book. Then maybe she'll go for a run. Phil offers to join her but Claire says she's pretty fast. He probably wouldn't be able to keep up. You think Phil's gonna take that?
Manny wants his new classmates to know that he's proud of his heritage, so he wears a traditional Colombian poncho. Gloria is very supportive of her son but Jay thinks he's just asking to get beat up. When Gloria sees the poncho in the trunk of the car, she knows that Jay convinced Manny to ditch the outfit. She forces him to go down to the school with her to return the poncho to Manny.
When they meet up in the school corridor, Manny pulls a pan flute from the poncho pocket. He plans to play some Colombian folk music for his new classmates. Gloria pulls Jay aside and tells him to break the pan flute. She was fine with the poncho, but if Manny starts playing folk music, she's afraid he's going to die a virgin. Jay concurs. He promptly destroys the pan flute in front of a horrified Manny.
As Mitchell baby-proofs the entire house, Cameron continues his project of photographing baby Lily as various pop icons. Today she's dressed as Diana Ross from the RCA years. Mitchell thinks the "ghetto-fabulous afro" Lily is wearing may be a little over the top. Cameron wants Mitchell to loosen up and encourages him to dance with Lily. Mitchell does dance with his daughter and accidentally bonks her head in the door jam. Ouch!
The guys freak out and rush Lily to the doctor's office. The doctor assures them that babies are designed to withstand new parents. She's fine and they are doing a great job caring for her. Mitchell isn't so sure. Cameron can change her diaper one-handed and all he does is slam her head into door jams. Cameron reminds Mitchell that he's the one who baby-proofed the house as well as being the person who dealt with all of the adoption red tape. Cam says, "Without you we wouldn't have a baby to injure."
They both feel better about things until they realize they've locked Lily in the car. As Cameron races around the parking lot in a panicked state, Mitchell calls for help. Moments later, a signal is sent and the car doors are unlocked, thankfully before a charging Cameron can smash the window with a trashcan.
All right, you knew this was coming. The race is on. It's Phil versus Claire in a two-mile jaunt through the neighborhood. The problem is that Phil doesn't run five miles a day like Claire. He power-walks with poles. As they do their run, Claire is on cruise control as Phil struggles to keep up. He rips off his sweatshirt. Underneath, he's wearing a t-shirt that says "World's Greatest Dad." Claire sees this and realizes the first day of school is hard for all her kids, including the one she married.
Claire tanks the race because she believes her husband could use a win today. Phil is in his glory. He dances around the driveway screaming, "Do you believe in miracles?!" The celebration is short-lived once Haley comes barreling up the driveway forcing her father to do a full-body flip over her driving instructor's car. It may be the most hilarious vehicular felony ever shown on television. Don't worry, Phil is fine. We're the ones in pain from laughing so hard.