Credit: ABC Family

Now that Spencer thinks she may have had something to do with Ali's death, the smartest Liar is starting to question everything she thought she knew, and we can't wait to see that drama play out on  Season 4, Episode 22 (“Cover Me”). Will Spencer finally remember a terrible truth, or will she realize Ezra's notes were wrong, after all?

The Canadian promo is also about Spencer and the mystery of her past, and it certainly makes tomorrow's episode look riveting. We've taken a close look at the promo to see what it reveals.

1. Spencer is freaking out. The promo opens with Spencer pulling the covers back to reveals a bed full of dirt. She gasps and pulls back. What do you think: Dream, drug-induced hallucination, or on of "A"'s creepiest moves to date? None of these options spell good news for Spence.

2. Holbrook has some questions. "There's a couple of things I'd like to ask you," Holbrooke tells Hanna at :06. We wonder if this new inquiry is related to that note Paige dropped off to the cops last week... You know, the one about Ali being alive?

3. Ezra wants to talk to someone. At :08 we see Ezra say, "I really want to talk to you." we see in this sneak peek that he's talking to Emily.

4. What did the Hastings cover? "You and dad said you covered for me that summer," Spencer reminds her mom at :11. We assume she's going to demand to know exactly what they were covering. (There is also a shot of the threatening note from "A" that we saw in the American promo.)

5. What did Emily figure out? At :14 we see Mona and Emily sitting in a car. "I'm surprised that it took you this long to figure it out," Mona tells Em. Given that the official synopsis of the episode says that Em takes over investigator duty, we're guessing this conversation is about Ezra and his shady behavior. We could be wrong, though.

6. Why is Hanna quizzical? At :14 se see Hanna at what appears to be dinner with a guy (Travis, maybe?). It looks like she's spotted something that's made her concerned.

7. Spencer remembers? At :17 we see a flashback, where Spencer appears to, well, attack Ali with a shovel. "How am I supposed to take responsibility?" we hear her say as the promo ends. Well, this certainly makes it seem like Spencer ends up thinking she did the dirty deed — but is she right?

Watch the dramatic promo for yourself here, and then sound off with your own thoughts in the comments:

Catch this episode of Pretty Little Liars on March 4, 2014 at 8 p.m. ET/PT on ABC.

Rebecca Martin is an Associate Editor at Wetpaint Entertainment and our resident Game of Thrones, Breaking Bad, and genre TV expert. Follow her on Twitter and Google+!