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.
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Since Charles is threatening to make his big entrance at the DiLaurentis house, it seems a little obvious that this is the point that the gals get wind of it, but will they all want to capture him?
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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.
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What are the significance of these animals to the episode? Did Mona throw one at Aria in the hopes that it would bite her and make her ill? Quite possibly. Nothing's shocking in Rosewood.
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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.
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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?!
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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!
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Someone clearly walks in to the laboratory and that's why the liars are in hiding. Where is Mona? Could she be helping the liars out, or has she done a runner? We have no clue!
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Pretty Little Liars Quotes

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.

Alison

Lord help the mister who comes between me and my sister.

Cece