Joanna finds a yearbook with Vivian herself sharpied out. And then at the page of the school ski trip -- yep, I thought that was going to come back -- she finds a picture of Mia, at 28 months. (Which obviously means we're in Chinatown, but Joanna's not there yet.) Also sharpied up is Vivian's mirror, which has crazy-person writing all over it. Joanna flashbacks to a secret hiding place on the roof where they would hide things for each other. Guess what, there's a USB fob in there.
Is chasing a bro out of the house when Joanna comes back in off the roof. He is wearing a knit boonie and a knapsack and a cute beard, so obviously he is a hacker or a paparazzo or something.
Mia: "Friggin' back off! I don't know anything, I shouldn't have called you..."
Joanna: "Everything okay? I'm just asking, not because I'm a cop or anything."
Mia: "We're having a disagreement, Houseguest. That okay with you?"
The guy, whose name is Remy but -- spoiler alert -- don't worry about it, finally leaves, and Mia immediately pulls out a bag of pills and acts real tough.
Joanna: "What's that pill you're eating?"
Mia: "My dead sister's Xanax, you got a problem? Because I'll just tell my mom I caught you stealing. That bitch is racist, she won't question me."
Joanna: "Oh my God."
Mia: "Why are you laughing?"
Joanna: "You are like, exactly the same as Vivian. Your 'sister.' She popped pills and was horrible also."
Mia: "Really, do you think so? Then I guess we can be friends."
This whole conversation Mia is making a ... concoction. I don't know, it's got milk and whipped cream and chocolate sauce in there, I don't know what else. It's like what a crazy toddler would eat on their first night in their own apartment. I guess there's cereal but we didn't see that part. And then she calls her concoction "dog food," so I dunno, maybe it's actual dog food. The script seems to think it makes more sense than it ended up making, is what I'm saying, but the takeaway is that Mia's idea of being an afterschool badass also involves making poor nutritional choices in front of company. "Take that, Food Pyramid!" Shoooooooshhhhh!