Emily receives an "A" card: At :02, Emily receives a postcard from "A". It's in French, and says "Arrete de creuser! LA police sAit dejA que c'est toi qui est cApAble de meurtre!" That roughly translates to Stop digging! The police already know it's you who's capable of murder.
It's worth nothing that the Ts seem to be capitalized as well as the As. A hint about Toby (Keegan Allen), or just a quick of handwriting?
Spencer is near breaking: Not only does the voiceover say "the breaking point is near," but at :08 we see Spencer (Troian Bellisario) curled up on her floor, looking pretty stressed out. We also see Emily and Hanna looking upset.
Spencer goes searching: At :12 we see Spencer enter a creepy looking room that appears to have pictures torn down. Part of her search for the truth about Toby?
Hypnotherapy: Dr. Sullivan is back, and wants Emily (Shay Mitchell) to undergo hypnotherapy to dig up repressed memories.
Emily's memories: Speaking of digging, Emily says she remembers "exactly what happened." We're shown a flashback of a distressed Ali screaming "what do you think you're doing?" while Emily raises a shovel, as if she's about to hit someone.