No "Magical Girl Aeria"... not today, at least.
The box of items is, of course, the "misc stock" box that Aeria was complaining about in Issue 2. With that in mind, I figure this story is taking place very shortly after that one. Maybe just a week or two later. All I know for sure is that it's supposed to be a Sunday, so nobody is around (and you'll notice they'd flipped the entrance sign to "Closed" on page 1) - this will either be worked into the dialogue somehow, or at worst just stuffed into a narration box at the start.