The mirror is large, big enough that she could step through an empty frame of the same size, and appears to be made of perfectly ordinary glass and metal. The ornate frame is elaborately carved into strange, swirling designs that seem to shift at the corner of her vision. 

When she touches the glass, it seems strangely soft beneath her fingers, as if her hand might sink right through it. A silvery mist begins to spread across the surface from the point of contact, obscuring the reflection. 

Oh! Well then, that's obvious, isn't it?

She steps into the mirror. 

Silver mist fills her vision, and there is a sense of disorientation, as though she is briefly weightless and in no particular location.

It passes, and she finds herself stepping out of the mirror into the attic.

Or, no, not the same attic, but its mirror image. The part she can see looks identical, since it would have been visible in the mirror. 

Well. Hm. 

... she should try to find her room. Is the way down still where it was before?

Correcting for the way everything has been flipped, the underlying shape and structure of the attic seems to be the same. The part that wasn't visible through the mirror, though, is clearly much more recently used, and is full of neatly-stacked boxes and papers.

There is a clear path to the trapdoor, which is in the same place as it was before, but it's closed and there's no ladder on this side. It looks like it can be opened from either side, though.

Oh! There are people here. Or at least a person. She should say hello. 

She opens the trapdoor, careful not to let it bang against anything.

The difference between this house and hers is greater here. The hallway below the trapdoor is clearly well-maintained, if cluttered and lived-in. More boxes are stacked along one side, and one has a stack of hats on top of it. 

There is still no ladder; she'll have to jump down, and it's not clear how she'll get back up if that turns out to be necessary.

Hmmm. 

Is there a box here filled with soft things? 

Yup! Most of them are full of boring things, like hats or old books, but the third box she tries is full of blankets, nice and soft and neatly folded. 

Alright then, let's toss that box down first so she has something comfy to land on. 

The box plummets through the trapdoor and lands with an audible thud on the floor below. 

There are footsteps in the distance, coming up from the bottom of the house.

Oh. She'll just sit here and wait for the person to arrive, then. Maybe they'll have a ladder.

Shortly, a man appears in view, wearing a top hat and a bright blue waistcoat. He looks down at the box, then slowly looks up.

He does a double-take when he sees Audrey.

"...hello," he says, absently taking off his hat so he can stare up at her without it falling off.

Audrey smiles.

"Hello! Are the blankets okay? I'm afraid I might have insulted them." 

"I...think the blankets will be fine. More importantly, who are you and how did you get into my attic?" 

"I'm an Audrey! I came through a mirror. Is this where isn't is?"

He drops his hat.

"You came through a mirror? From where?"

She points. "Back that way."

"Yes, I see that..." 

He thinks for a moment, composing a better question. "Where were you before you came through the mirror?"

"... Earth, I suppose?"

"Well then." He holds up a hand, inviting her to jump down.

"Welcome, Miss Audrey, to Wonderland, which is not on Earth, or at least not the Earth you just came from. I am known as the Mad Hatter, and this is my house."

She hops down, landing with a pluff in the box of blankets. Accepting the Hatter's hand for balance, she stumbles to her feet, and sways. 

"Nice to meet you!" 

She looks him up and down, her eyes not quite focussing. 

"Um. Do you have any food?"

"Nice to meet you too! Right this way, I'll find you something to eat." He leads her back down the hall in the direction he came from.

"Oh, I should probably warn you about Wonderland food. A lot of it has strange effects unless you take even numbers of bites; I don't think that happens on Earth?"

Audrey blinks. "Um, not that I know of. I don't suppose you could just pick something with a nice effect? Maybe making my hair pink? I like my hair being pink."

"Well, I can certainly get you strawberries," the Hatter says, amused, "but you should probably eat other things as well. Bread is one of the few foods that doesn't do anything, if you'd rather not risk forgetting the numbers thing," he offers.