The promo, which you can watch above, is mostly old footage, but there are also a few very revealing new scenes. First, the Rosewood High principal tells Aria, "It's a felony for a teacher to have sex with a minor." He throws down photos of Aria and Ezra kissing. "Ezra Fitz is going to prison."
And in case you think that's just an idle threat, the promo closes with a shot of what appears to be Ezra actually being taken out of school in handcuffs. O.M.G.
On one hand, we did not anticipate this plotline popping up right now (especially since Aria and Ezra are actually broken up at the moment). On the other hand, we're not shocked that Ezra's law-breaking eventually came back to bite him. Having sex with your student is always risky, but when the "A" team (and possibly "B" team) is after your girlfriend, things are guaranteed to go downhill eventually.