She's not there but Damien is. He sold Juliet the drugs she used to KO Serena.
They go to Juliet's mom's house and she reveals the connection to Ben - she's Juliet's half-brother.
Through flashbacks we learn that Serena did go on a roadtrip and stay in a hotel with Ben while a minor at his prep school, but that they never slept together.
Meanwhile, Juliet decides to come clean and track Serena down at the Ostroff Center.
We finally learn that it was Lily who used the gossip about Serena to blame Ben and get her back into Constance. Only Ben ended up going to jail.
The gang lets Juliet off the hook. Now Serena is on the outs from Lily, and as the credits close, she goes to visit Ben behind bars.
Meanwhile, Dan and Blair stay in the city and may be being set up as a couple ... gulp.
Elsewhere, Nate's mom shuts down his dad when she feels he's up to his old ways, but Nate offers him a place to stay when he gets out of prison, saving him the embarrassment of the halfway house.
Finally, Lily had planned to sell Bass Industries without telling Chuck, sending him off to New Zealand, where he may or may not be teaming up with his Uncle Jack to save the company ...
(Source: TV Fanatic)