19. Dr. Estrangeloved

When Lily's ex-husband, Dr. William van der Woodsen ( William Baldwin ), shows up unexpectedly in Manhattan, Serena finally gets the reunion she has so desperately wanted with her father, but the circumstances turn out to be far from ideal when Will reveals a secret of Lily's ailing health. When Serena and Nate continue to have relationship issues, a scheming Jenny is more than happy to be a shoulder for Nate to lean on. Meanwhile, Dan finds out that he did not get accepted into the Tisch writing program and Vanessa admits she may have been somewhat responsible by acquiring the spot that Dan wanted in the first place. Title reference: The 1964 film Dr. Strangelove.