6 Secrets Revealed on 'Pretty Little Liars'

Masks! Melissa! A potential Ali twin! Last night's Pretty Little Liars proved to be pretty epic — specifically because of all of the intel we got about this season's major mysteries. Here's what we learned on last night's episode:

Melissa isn't 'A'... and has (probably) been protecting the girls this entire time.

Melissa's always been highly shady. From faking her pregnancy to hanging out with Jenna to always having THE PERFECT hair, there's always been something awfully mysterious about Spencer's big sister. This week, we learned that the Melissa masks that the girls found in the costume shop were actually an exchange that Melissa made with the creepy mask maker for information. When Spencer confronts her sister, Melissa tells Spencer she was on the Halloween train, but didn't try to hurt anyone — that was all Detective Wilden. Melissa suspects that Ali is still alive — she's been trying to protect the girls, not hurt them. Which maybe means that she was the one who killed Detective Wilden — and, maybe, also her fiancé, Ian? Time will tell.

Ashley could have killed Detective Wilden. But Melissa could have too.

While 'A' has a knack for making people's lives a living hell for no reason, it turns out that there is a good chance that Ashley was the one who killed Wilden — or, at the very least, has seriously incriminating information about who did. Poor Hanna — even she believes Mom is guilty. Spencer, on the other hand, isn't so sure. After her conversation with Melissa, it seemed pretty evident that Melissa was hiding something in regards to Wilden's death. So, which family will be sending one of their own to jail in the near future? My guess is that either way, they'll find a way to wrangle themselves out of the crime.

There's more to Toby's Mom's death than we thought...

We figured that Toby's mom's death was just leverage from 'A' so that Toby would do "her" ("It always felt like a she, didn't it?") dirty work. But now it seems that Toby's mother's death is connected to the overall mystery. When Toby's mother's former psychiatrist (who has developed Alzheimers and now lives in his own "Radley") told Toby to have his mother keep away from that "blonde girl," we can't help but wonder if it was Ali — or, rather, Ali's twin — who drove Toby's mom to madness.

Detective Wilden set the fire.

If we believe Melissa, that is. Apparently, it was Detective Wilden who tried to send the liars to a fiery grave — Jenna and Shana were simply at the cabin to see who Red Coat was.

Red Coat pulled the girls out of the fire.

Melissa confirmed that a girl in a red coat pulled the liars out of the burning cabin, once again leaving us with the question of whether that person was actually Ali... or just a person in an Ali mask.

Aria's not capable of a healthy romantic relationship.

It's bad when your own mother can date guys your age better than you can. Aria's still hung up on Ezra, and even Jake's ripped karate body isn't enough to distract her. Get a grip, Aria!

Image: ABC Family