Five yards. Something panted just behind her.

She threw herself at the hydrant, an unimpressive black stub of metal barely two feet high. But as she did, a heavy scorching weight collided with her back, slamming her to the ground and pinning her there. She wrenched her head round enough to see the huge dog-like creature crouching on top of her. It wasn’t quite burning her, not yet, but its body was as hot as a banked stove. And she knew, if it wanted to, it could get much, much hotter. Its eyes were vicious coals in its flaming head, and when it opened its mouth, baring ragged teeth, a line of searing drool dripped across the back of her neck. Go on, try it, it seemed to be saying. Just try something. Give me an excuse.

‘Hydrant, burst!’ Irene screamed.

The hellhound opened its jaws wider in lazy warning.

The hydrant exploded at approximately knee level. Fragments of twisted iron went spraying out in all directions with the first intense burst of water. Irene was torn between thinking Thank goodness I’m on the ground and That’s what comes of sloppy vocabulary and word choice. A bit of metal sheared through the air a few inches above her nose and slapped into the hellhound almost casually, sending it cartwheeling backwards with a howl of pain.

It took Irene a moment to pull her wits together and scramble to her feet. The water should slow the hellhounds and douse their fires for a while, but she didn’t have any other backup plans. And she still had to get to the school library. Her dress wet and her shoes soaked through, she broke into a stagger, then into a run.

The library doors were made of heavy studded wood, and when she yanked them open, warm lantern-light spilled out over her. Making you a target for anyone looking in your direction, her sense of self-preservation pointed out. She stumbled into the vestibule and swung the heavy door closed, but there was only one large lock on the door, and no key. But then again, she didn’t need one.

She leaned over and murmured in the Language, ‘Lock on the library door, lock yourself shut.’

The sound of tumblers moving into the locked position was very satisfying. Especially when the next noise, a couple of seconds later, was the heavy thud of hellhound hitting the door on the other side.

‘What’s going on there?’ an annoyed voice called from deeper inside the library.

Irene had scouted out the place earlier, with a duster and wax polish as an alibi. Directly ahead were the non-fiction stacks, shelves full of books on everything from astrology to Zoroastrianism. And to the right, there was a small office where books were stored for mending. More importantly, the office had a door she could use to get out of here and that was what she needed.

There was another thump from behind her. The main door shivered slightly under attack, but stood firm.

She didn’t bother replying to the voice she’d heard. Instead she brushed the gravel from her clothing, forcing herself to calmness. The atmosphere of the place soothed her automatically; the rich lantern lights, the sheer scent of paper and leather, and the fact that everywhere she looked, there were books, books, beautiful books.

Another thump from the outer door, and the sound of raised angry voices. All right, perhaps she shouldn’t relax too much.

She stood in front of the closed office door, taking a deep breath.

‘Open to the Library,’ she said, giving the word Library its full value in the Language, and felt the tattoo scrawled across her back shift and writhe as the link was established. There was the usual flurrying moment of awareness and pressure, as though something huge and unimaginable was riffling through the pages of her mind. It always lasted just that little bit too long to bear, and then the door shuddered under her hand and opened.

A sudden burst of noise indicated that her pursuers had managed to enter. She spared a moment to regret that she hadn’t had time to grab any other books, and quickly stepped through. As the latch clicked shut behind her, it re-established itself as part of the world she’d left behind. However many times they might open it now, it would only ever reveal the office to which it originally belonged. They would never be able to follow her here.

She was in the Library. Not just any library, but THE Library.

High shelves rose on either side, too high and full of books for her to see what lay beyond. The narrow gap in front of her was barely wide enough to squeeze through. Her shoes left wet prints in the dust behind her, and she stepped over three sets of abandoned notes as she edged towards the lit area in the distance. The only sounds were a vague, half-audible creaking somewhere to her left, irregular and uncertain as the slow oscillations of a child’s swing.

The cramped space abruptly opened out into a wider wood-panelled room, with a wooden floor. She glanced around, but couldn’t identify it offhand. The books on the shelves were printed, and some of them looked more modern than any from the alternate that she had just left, but that in itself proved nothing. The large centre table and chairs were covered with dust, just like the floor, and the computer sitting on the table was silent. A single lantern hung from the ceiling, with a white crystal burning brilliantly in the centre. In the far wall, a bow window looked out over a gaslamp-lit night-time street, and a wind tugged at the tree branches, making them silently bend and sway.

With a sigh of relief, Irene sat down in one of the chairs, brushed loose gravel out of her hair, and drew the stolen book out of her hidden pocket. It was safe and dry. Another job done, even if she had been forced to abandon her cover identity. And she’d even given the school a legend. The thought made her smile. She could imagine new boys being told the story of The Night Turquine House Got Burgled. The details would expand over time. She’d eventually become a world-famous master thief that had infiltrated the place in disguise, seduced half the teachers, and summoned demons to aid her escape.