It was about 9pm and the party was getting into full swing; some people were dancing; most people were drinking; some people were standing by the drinks table, watching the wall with the projection of videos and pictures of a timeline of Serena from childhood till present. Serena was surprised her mom had even bothered taking all these pictures and videos of her. She always had the impression that her mom didn't really care. Sure, Lily was hardly mother of the year, but she did love Eric and Serena more than anything, even if she didn't show it. She preferred to add more men to the list of Lily van der Woodsen's ex-husbands than spend time with them. Her name was actually Lily Rhodes, but she felt that van der Woodsen (the name of her first husband and Serena and Eric's father) commanded more respect in the Upper East Side. Anyway, Serena's daddy issues out the way, she thought it was pretty cute of her mom to make her this slideshow, and it more than made up for the lack of imagination with the Chanel clutch.

Only Serena van der Woodsen would complain about being given Chanel handbags.

The timeline was starting to get to Serena's more recent years and Kati and Is took that as their cue to text Blair to continue on with the next part of the plan. If you haven't already noticed, Kati and Is are pretty much a package deal; you won't find one without the other.

Blair was at home, ready. She got Kati's text and decided to speed things up. She called Dan and told him she'd pick him up instead of him coming to her. She got in her town car and it barely took her twenty minutes to make it to Serena's place with him. They were in the car, waiting downstairs because Dan was freaking out. Blair tried her best to pretend she gave a shit about him and she offered a few reassuring words about how she and Serena were fine and she'd already told her and she was fine about it.

Yeah, okay then, Blair.

Blair really couldn't care less about Dan. She didn't want a relationship with him; she only ever wanted him because he was Serena's and she wanted to prove that whatever Serena 'did', she could 'do' too. As soon as everything went down and Dan realised she was just using him, he probably wouldn't want to talk to her anyway. It was a win/win for Blair.

Back at the party, Lucas was off in Serena's room, taking a call (probably from his mom, making sure he didn't stay out too late). Serena was talking to Penelope and Alyssa, on the sofas, just as Dan and Blair appeared from the elevator to the penthouse.

Heads turned and the whispers began. Serena heard all the commotion and turned around to see what all the fuss was about. She froze when she saw Blair and Dan arrive together. She hadn't put two and two together yet, but their presence separately was enough to put Serena on edge. She turned back around and tried to compose herself; she took another flute of champagne and practically downed it as she saw Blair coming towards her- Dan didn't have the nerve, so he hung back, by the bar.

"S! Happy birthday, babe! You look great. I'll give you your present a little later on- it's still not quite finished." Blair hugged Serena, putting on a show for everyone. Making a huge display- making sure that everyone knew she'd arrived.

Serena couldn't exactly make a scene and ask Blair what the fuck she was doing. She couldn't figure out if Blair was up to something or if she'd genuinely just got amnesia and blanked on the part where they clearly weren't on great terms. Serena had no choice but to make nice and act as if nothing had ever happened and they were the same old Blair and Serena

"Hey, B! Thanks." Serena tried to hide her displeasure and was thankful when Blair decided to leave her and say hi to everyone else.

"S, excuse me while I go and say hi to a couple people. I'll be back in a bit." Serena and Blair exchanged the fakest smile that's ever graced the earth before Blair disappeared off somewhere to be a continue being a biyatch.

"Kati, you block Is and make sure no one sees. Is, you take this," Blair handed her a memory stick with Serena's 'present' on it, "put it in the laptop over by the projector. It's 9:56 now- press play at 10pm…on the dot. Don't fuck this up." Blair walked off to get Dan…

Chuck was waiting in the wings for his cue to do his bit. The adrenaline was pumping; Chuck lived for times like these.

Blair grabbed Dan, took his face in her hands and proceeded to shove her tongue down his throat. He was a little shocked, but he went with it. Once again, all eyes turned to them. Serena's eyes were fixed on them. It was the last thing she wanted to see but she was too heartbroken to move. A lump formed in her throat as tears filled her eyes. She struggled for air, and she covered her mouth to prevent herself from bursting into tears.

How could Blair do this to her? And why did she have to do it like this? She knew how much Dan meant to her. What did she do to her to deserve this? On her birthday.

All eyes diverted to Serena to see her reaction. Serena got up, unable to handle being in a room with all these people just waiting for her to explode. Helplessly looking around, she tried to figure out the quickest way to get out of the penthouse-

10pm…

Chuck pulled the plug on the music, just as Is pressed play on the laptop…

Onto the giant wall of the lounge was projected a video of Serena from boarding school just over a year ago…

Everyone gasped in unison and stared up at it. Serena stopped in her tracks and could do nothing but watch with them; she was already too far away from the laptop to do anything about it. She recognised from the intro (a drunken sixteen year old Serena speaking into the camera while she set it up) what the video was. She wanted to be sick. Was this really happening?

The video cut to Serena and an unknown guy on a bed. Sixteen year old Serena was busy going down on an unknown guy, while eighteen year old Serena glanced over at Blair, powerlessly, with sad, hurt eyes as if to ask why she was doing this. Blair's eyes replied coldly and unfazed as she joined in with the mocking and laughing that was going on amongst everyone else.

Just as sixteen year old Serena had taken a break from to do a line of coke- Lucas emerged from Serena's room after having finished his phone call. He blinked when he saw the projection and he cut his eyes to Serena, who was standing alone, in tears. She looked up and caught his gaze- he looked so disappointed in her. She felt her heart stop when she saw him. Lucas, of all people, could not know this side of her. She opened her mouth to try and explain herself but no words came out.

Lucas thought it best to leave when the projection got a little too pornographic for his liking; ever-considerate Chuck had turned up the speakers, just to make sure everyone could hear clearly.

He picked up his jacket from the arm of the sofa, walked straight past Serena and headed for the elevator. He repeatedly pressed the elevator button impatiently as a desperate Serena hurried to follow him out. "Luke, wait! Please!"

Lucas turned around and put his hands out, warning her to keep her distance. "No, Serena. Just stay away from me."

Serena started to cry harder, begging him to hear her out. "Please, Luke. It's not what it looks like; I can explain. Please. You have to believe me. That's not me anymore."

"You, know, you always say that you're not like these other girls, Serena. Well, from where I'm standing, maybe you aren't so different from these people after all. You know what? Maybe you're worse."

Lucas stepped into the elevator. Serena's whole world had just fallen apart and the last good thing left had just deserted her. She didn't know what came next; she didn't know if things could get any worse, but she knew she'd never forget her eighteenth birthday- the day everything changed.

Just as the elevator door was closing, Serena interrupted the stabbing silence between them, "I'm sorry that I'm not who you thought I was…but if you can't accept that, then you're not who I thought you were either…"

The elevator door responded for Lucas as it shut in Serena's face, leaving her standing there alone. After a pause, her tears turned to hysterics and sadness turned to anger. She went back to the lounge and screamed for everyone to get out before she ran off and took the service elevator out of her apartment and as far away as possible.

Happy birthday, S.