Rufus hisses and weaves and lisps at the unflappable Dr. Sandiego until their wife comes home. Lily's moderately pleased to see Rufus, and disturbed by the presence of Wills, but mostly this scene suddenly becomes about Serena, who hasn't seen her father in fourteen years and spent the better part of the summer looking for him under every rock and bridge on the Continent when she wasn't letting yacht-owning Eurotrash drink Belvedere off her tits in Ibiza. Her mouth goes bwuh?; her issues sigh, and finally arise from their disco nap, because it is time to DANCE!
After some Timmy-in-the-well style whining-barks from Rufus, Lily spills the story, which is that every word she's said this entire season has been a lie. "It wasn't my mother who was sick. It was me. And that's why William and I were together last summer. He wasn't treating CeCe. He was treating me." Which, we've pieced that together, fine. But when it gets wicked ridiculous is when the scene starts answering questions we didn't need to discuss, because of how silly it all gets so instantly: "I wanted to see you [Serena], but as her doctor, I couldn't tell you why I was there [in Santorini], and I... I didn't want to lie."
See, because Dr. Sandiego is so dedicated to his medical ethics that he didn't even want to look his daughter in the eye -- as she was going visibly, globally slut-crazy -- on the off chance that she might say, "Hey, I know for a fact you are here on this continent so I just thought we could hang. These hors d'oeuvres are great. So listen, any chance my mother has a mysterious illness that only you know about, or can treat, so she's pretending to be at my grandmother's place in the Hamptons?" And he would have to be like, "Mmm, noooooo. No, that's not what's going on." And that would be a lie. He would have lied.
"The one bright spot is that Lily's illness is very treatable," Will explains. "We're just waiting on the last round of test results." If you wondering why this "illness" is so sketch and mysterious even though it's 2010 and we have names for like most diseases, it's because there is something sketchy about this illness and we don't know what it is yet. I mean, I don't want to blow your mind, but the guest star around whom this short end-of-season story arc revolves, he's sort of sketchy. Unlike the usual people who show up on this show for a few episodes and end up changing everybody's lives for the better with their soothing, gentle natures and warm words of encouragement.