She'd grown up with it, the big blue box. It had always been there in the forest, just beyond the shoreline of the lake near her house, as normal and unquestioned as the trees around it. A lot of junk ended up in these woods, it was the perfect place to dump anything big and clunky you didn't want anymore. Every now and then a rusted-out, gutted car-husk poked up from the vines and moss and dead leaves covering the forest floor. Here and there were old traffic signs and traffic cones that stupid or drunk teenagers had stolen and abandoned as practical jokes or simple vandalism, and it wasn't difficult to stumble across the derelict remains of a once-hidden shelter where boys would stash their cigarettes, beer, or Playboys from their parents' suspicious eyes. These woods were rich with the secret history of human beings, abandoned and almost forgotten now thanks to the highway built years and years ago that made the county route skirting the forest's edge that led to her house obsolete.

She loved exploring those woods, for this very reason. As long as she could remember, since she was barely big enough to go out alone, she spent all her free time exploring the, eventually taking notebooks and paper with her to make logs and maps, charting the man-made "landmarks" as she discovered them. Her curiosity was insatiable, and her concern for personal safety was almost nonexistent. But nothing captured her imagination quite like that mysterious blue box.

She didn't know what it was. She'd found it a long time ago, when she was a little girl. And it was the most interesting thing she'd ever found. It was old, very old, and it had been buried beneath years of plant growth and death, covered with vines, mosses, leaf-mulch, and animal droppings, when she'd first spotted it. Since then she'd cleared so much of that away, and found writing on it, words like Police Public Call Box across the top, a torn sign covering a disconnected old touch-tone telephone with words like Public and Phone in crisp black letters and Pull to Open on the very bottom, and a warped, half-dissolved sticker with a few letters that didn't spell anything recognizable on one panel. Where it was exposed to the sun its paint was faded and fractured, but deep beneath the preservative forest coat, it was blue as blue could be. Its windows were oddly intact and not even cracked a little, but the light casing on top was broken, the metal twisted out of shape and the bulb inside missing except for the piece that screwed into the socket.

But there was more than that. There was so much more. It wasn't just some abandoned phone booth. Inside…it was nothing short of magical. It had been closed when she'd first found it, sealed shut by the amassed plant matter crowding around it, but she spent those long weeks prying it from nature's grip, and one day, one unforgettable summer, she came to clean more of it, and its doors lay open. Unbidden, unexplained. And inside, it wasn't just an empty box.

By now she'd figured out that it was a portal. A magical portal to this big house somewhere else. when she first walked in, she saw a big, six-sided machine covered with knobs and buttons and levels and wheels and any other control one could think of in a giant, multi-level room with corridors upon corridors she followed one by one that lead away to other places like kitchens and libraries and bedrooms and offices and studies. Nearly everything was in a strange language she didn't recognize, though, or adorned with beautiful circular designs. Some of the books in the library were even filled with those circles, and most others didn't seem to have any sort of pattern to their alphabets when compared to each other. Curioser and curiouser, though, there were parts of things here and there that were written in letters she could read, in plan English, even. What looked fascinating and complex and thrilling at first glance made absolutely no sense just beneath the surface.

She set about trying to map it and spent years trying, but nothing was more fascinating or more frustrating to a recreational cartographer than the inside of this box. Its layout didn't physically make sense! She tried two-dimensional drawings when she was young, then brought shoeboxes to try to make a scale model as her spacial understanding grew with age, but every time, things ran into each other, rooms overlapped, corridors crossed on the model where they didn't as she stared down them. She measured exact angles, meticulously recorded room dimensions, and scrapped draft after draft as they led invariably to architectural impossibilities. The entire inner workings of this strange place that the blue box led to was an enormous spacial anomaly.

She never quite gave up finally understanding the place, though. She never told anyone else about it; it was her secret world inside the forest, a treasure trove within a treasure trove. It was her life, her passion, to discover everything about it even if she couldn't make sense of most of it. Foregoing human interaction and normal life for the sake of this all-consuming curiosity, she never put much effort into peer friendships at school. It would have worried her parents more if she wasn't instead a stellar student, her passion to figure the box out leading her to learn and memorize everything she was taught and more in the vain hope that something, perhaps mathematical, scientific, historical, or even literary, would shed the tiniest touch of light on anything in those endless rooms.

None of it mattered, though, in the long run. Or maybe all of it did. Regardless, everything changed that fateful day she discovered the Chameleon Arch. She didn't know what it was, of course. She was just playing around with a brand-new set of controls she'd found in a hidden panel in the wall of the main room, and this strange, wiry, semicircular thing dropped down from the ceiling on a cable and hung there, at eye level, tarnished but inviting.

Of course she tried it on. She instinctively tried to make anything work at all in this dead place whenever she was exploring.

Nothing could have prepared her for what happened next.

The most splitting headache cleaved her skull in half and pulsed down through her body. She let out a piercing scream, but not an instant later it was drowned out by a grinding roar like an enormous, corroding, metallic beast freeing itself from chains. A heavy piston set in a clear column rising from the center of the six-paneled machine nearby dragged itself downward, adding a squeal of metal-on-metal to the thunderous noise, then pumped back upward again, and down a second time. She struggled with the clamp on her temples, dizzy, deaf and blinded by the sensory overload. It didn't let go, though. She thrashed violently against it, her screams fighting for dominance over the machine's. And then everything dissolved.

The Chameleon Arch dumped her limp body unceremoniously to the floor when it finished. The piston lowered to its final position, and the groaning roar quieted to an idle thrumming. She lay facedown on the dusty floor, motionless. Brand-new twin hearts pounded out a rhythm the likes of which hadn't been heard in the TARDIS for years.