Departure (2019)

S2E24 Valley Girls

In an 80s flashback, 17-year-old Lily Rhodes is expelled from boarding school and escapes to Los Angeles, where she reunites with her parents, Rick and Cece, and her sister, Carol. Fast forward to the present, Blair and Nate experience prom night together, but things don't unfold quite as they had hoped, thanks in part to Chuck and Serena's interference. Meanwhile, tensions rise between Serena and Lily following Serena's recent legal troubles, leading to a clash of opinions between them.