2x24 Valley Girls

In a flashback to the 80s, 17-year-old Lily Rhodes gets kicked out of boarding school and runs away to Los Angeles, to reconnect with her parents, Rick and Cece, and sister, Carol. Back in present day, Blair and Nate attend prom together, but the evening doesn't turn out exactly as planned. Chuck and Serena seem to have a little to do with that. Serena and Lily don't see eye-to-eye over Serena's recent run-in with the law. No Doubt performs in the flashbacks as an 80s band called "Snowed Out."