This One Clue Suggests Alison Knows About Mary Drake After All On 'Pretty Little Liars'

Pretty Little Liars is full of shady family members (umm, Melissa Hastings ring any bells?) but perhaps the most sketchy of all the PLL familial relations is also the newest one. Mary Drake was revealed in the Season 6 finale to be Jessica DiLaurentis' identical twin, and it totally changed everything we thought we knew about the (already super messed up) DiLaurentis family. Mary certainly won't be winning any Best Auntie awards since she worked with Dr. Rollins to lock Alison up in a mental institution, but while Mary may have spent most of her life lurking in the shadows, there's one big reason to suspect that, perhaps, she hasn't always been the DiLaurentis family's dirty little secret. Is it possible that Alison already knows Mary as her mother's twin? One clue suggests that Alison did know that her mother had an identical twin.

As stated in the Season 7 premiere, Mary spent years in Radley following an incident where a child in her care died. She was released from Radley 23 years ago, which is about the same time that the Liars and Alison were born. It's unclear where, exactly, Mary has been since being released from Radley, but given the stacks of world traveler books, it's possible that she's been traveling the world far away from her "jealous" sister Jessica. Though we haven't seen Mary in Rosewood, that doesn't mean she hasn't spent any time with Alison. In fact, one major clue from the Season 6 finale hints that it's possible Alison knew very well that her mother had an identical twin, even if she hasn't talked about it on camera.

In the Season 6 finale, Mary and Dr. Rollins go through with their plan to "gaslight" Alison and make her believe that she's seeing hallucinations of dead people. Mary dresses up as a zombified Jessica, while Dr. Rollins appears as Detective Wilden in a hyper-realistic mask. Dr. Rollins revealing himself to be the person under the Wilden mask was downright shocking, but why was it necessary? If Alison truly believed that her mother was dead, wouldn't Mary appearing as a dead Jessica be enough to send Alison into a mental breakdown? It would be, for sure — unless Alison already knew that Jessica had a twin.

Consider this: if Alison only saw her "mother" standing in the window of her house, she may assume that it's actually Mary, not Jessica, and not freak out as much. That's why Dr. Rollins had to make sure that he freaked Alison out with someone who was definitely dead and gone — Detective Wilden.

So what does it mean if Alison already knows about Mary? It could mean that Mary might have been involved in Alison's childhood more deeply than we could have expected. Perhaps Alison got the idea of Vivian Darkbloom — aka Alison's alter-ego — from the dark-haired Mary. No matter how these ladies really connect, there definitely could be more to Mary's story than we ever thought — and she may not be the stranger the Liars see her as.

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