Since the rapist wore a mask, the three victims try to pick him out from a voice lineup. Caitlyn is the only one of the three to pick out Noah, although she doesn't know it's him, at least not at first. But in one of those "victim accidentally bumps into her attacker" situations, she realizes Noah did it. The SVU detectives really need to be WAAAAY more careful about that.
Christopher's not going home with the Siberts any time soon, so Noah gives Christopher a big sloppy kiss. Bad idea, because the detectives scrape off a DNA sample, even though the rapist didn't leave any DNA behind. But you never know, right? And in a twist that only a SVU-watching novice wouldn't see coming, the DNA does match up with yet one more victim: Gwen herself.
Gwen doesn't believe it, until Noah tries to get her to admit that the sex was consensual. So she knees him in the balls. The ADA magically gets him to plead to the max by threatening to tack on an extra 25 years because targeting a specific group of people could constitute a hate crime. Other plots that need wrapping up: the spending spree on Elliott's credit card? Daughter Kathleen and her new boyfriend, heretofore unknown to Elliott. And Fin's transfer? The officer in charge's ex-wife had a little thing for Fin. So he's not going anywhere. Kim wants to go out for a drink to celebrate the only good news the unit has (that would be putting Luke Perry in jail), but Olivia's not there.
She's in counseling, because almost getting raped in the prison has really messed with her head. As usual, she's taking it pers-- oh, well, I suppose it's entirely appropriate in this case.