According to the official episode description, Aria and Emily are NOT interested in capturing him, while Hanna and Spencer get set to hatch a plan to rid their lives of this vile tormentor. It's a little weird that Aria and Emily wouldn't want to help.
Mike takes a break from Beacon Hills in order to stir up some drama for some old friends. We have yet to witness any scenes with him and Mona since she like returned from the dead, so this should be super interesting.
This is the picture that might prove that the liars are there for Mona, rather than Lesli. She knows something and based on her acting normal, this could be her new lair and it would be a perfect cover up.
Mona does not look impressed. Throughout these stills from the episode, she is the only one who has remained calm and that raises our suspicions that she is back to being the master manipulator. Did she ever have a break?!
Spencer and Hanna are back out of hiding and ready for the truth, but where exactly is it? I'm will to guess that some part of it will be in that cage. Are A's threats tested on animals? I wouldn't rule it out on this show!
You think the truth is this big shiny disco ball of purity then go ahead and try it. See what it gets you. Telling the truth to the wrong person at the wrong time is how I ended up where I did. Take it from me you're always better off with a really good lie.