The original A finally revealed to all of the Liars that she knows about Endgame in Tuesday's episode and the final sequence proved that once again, Mona is up to far more than she let on about. It definitely doesn't look good, but it's also not enough to say that she's working for the enemy.
Here's what we know: Mona is the smartest of all the people that Charlotte (Vanessa Ray) targeted in the doll house. The Liars only call upon her when they've gotten themselves in so much trouble they see no other way out, and honestly that's not only disrespectful but puts Mona in a much more difficult position than if they'd just included her in their plans in the first place.
Mona's love of the game has been no secret since Season 2. Her admiration of A.D.'s craftsmanship was undeniable, but does that mean that she's in league with the uber stalker? Not exactly.
Mona pointed out in the episode that she helped the Liars cover up Archer's (Huw Collins) murder, making her an accessory to the crime they are being blackmailed for. If A.D. takes them down, A.D. also takes Mona down. The postings she had on the wall are to help her figure out who A.D. is without any of the drama the Liars tend to create. As for the shovels, well, would you prefer Mona or Detective Furey (Nicholas Gonzalez) have them? Mona is the last person to let the most crucial evidence in the case fall into the wrong hands. Spencer (Troian Bellisario) is running around signing her name to receipts that tie her directly to the murder. Obviously, Mona can't trust the Liars to handle the situation.
It's easy to suspect that Mona is playing for the wrong team. We've all made that assumption because Mona was the first one to betray the girls. However, it's also been said time and time again that Mona has spent enough time repairing her reputation with the girls. She's bailed them out of their toughest spots and this time around, it might be time to trust that Mona is just taking the investigation into her own hands rather than depending on the girls to give her the info she needs.
There are only a handful of Pretty Little Liars episodes left, so you can expect the red herrings to be jumping out at every turn. Mona is definitely up to something, but if we have to place a bet we're going to say she's doing something more helpful to the Liars than harmful.
Pretty Little Liars continues Tuesdays at 8/7c on Freeform.