If there’s one Pretty Little Liars character we love psychoanalyzing the most, it’s overachieving brainiac Spencer Hastings (Troian Bellisario). But to be fair, she psychoanalyzes everyone else. Lately, we’re intrigued by a secret about the night Ali “died” Troian mentioned Spencer has been hiding from the Liars since the beginning of the show. What is Spencer’s big secret? We speculate below!

Spencer’s disappearance that night

As you may recall from the PLL pilot, the night Ali disappeared, Spencer wasn’t with the Liars when they woke up and noticed Ali gone. She came in shortly after they had awakened, and told them that Ali had disappeared. It seemed strange even then, but now that we know Ali is alive and Spence is hiding something, we wonder what went down with Spence that night.

Troian told Wetpaint Entertainment at the screening of the PLL Halloween episode, “You get to learn the most fun secret about Spencer, and that’s why wasn’t she with the rest of the girls when they woke up and why was she awake to hear Alison scream,” Troian told us. “As we’re going through the season you’re hearing a lot more and understanding more about the night and Spencer’s state and why she had the fight with Alison.”

What was Spence’s “state” that night? Well, when she wanders back into the sleepover, she seems almost numb with shock. She tells the other Liars: “[Ali]’s gone. I looked everywhere for her. I think I heard a scream.” Where is she coming from? Apparently, not just looking for Ali.

The Ian theory

Our theory is that Spencer’s disappearance had something to do with Ian, aka Melissa Hasting’s boyfriend at the time. Spencer and Ali had gotten into a fight earlier that day about Ian. Ali had seen Ian and Spencer kissing and told Spence that, if Spencer didn’t tell Melissa about it, then she would. Spencer agreed to tell Melissa that night, but told Ali that she was “dead to her already.” (Awkward.) We think Spence disappearance that night was because she went to give Ian a heads-up about her impending confession to Melissa.

This theory is particularly supported by a series of tweets we’ve gotten from the PLL cast. Andrea Parker (Mrs. DiLaurentis) recently sent out this pic of she and Ryan Merriman (Ian) together, implying that he might appear in a future PLL episode. We also have a tweet from Troian complaining about Spencer’s pilot outfit, implying we will be flashing back to that night in an upcoming episode. Did Spencer meet up with Ian that night? Did he try to hurt her? He’s certainly capable of it, given that he tried to do it again in the Season 1 finale when he tried to push Spencer off of the bell tower. Whatever happened, we think a meet-up with Ian would explain a lot.

What do you think Spencer’s big secret is? Share your theories in the comments below!

Catch the Pretty Little Liars Season 4 winter premiere, Tuesday, January 7, 2013 at 8 p.m. ET on ABC Family.

Credit: Celebified Photo: Tyler Blackburn Of Pretty Little Liars Fame Says He's Not Leaving "haleb" Behind With His Move To Raveswood!