“Air will feed the fire,” Tamani countered.

“But it will also let the smoke escape,” Yeardley said, tossing out two more buckets. “The smoke will kill us before the fire. Once it’s under control, we should be able to organise an evacuation. We’ve plenty of windows and ropes, not to mention firewalls, throughout the Academy. Wouldn’t be much of a research facility if we weren’t prepared for a fire.”

Tamani’s brow furrowed. “Klea’s soldiers are waiting out there, with guns. What’s to stop them from killing anyone who goes out the windows?”

“I’m afraid that’s not my area of expertise,” Yeardley said with a meaningful look at Tamani’s spear.

Laurel breathed and her throat was instantly burning, as were her eyes; the smoke was getting lower.

“The dining hall,” Yeardley croaked, ducking low and waving for them to follow.

As they approached the double doors, Laurel caught sight of the bucket brigade, already passing water from the fountain down the halls to keep the fire at bay. Others were stripping the walls and floors of flammable material to halt the fire’s progression. But their work was hampered by the acrid smoke, and for every faerie doing something useful, three were running blindly through the halls, clutching books and experiments to their chests. Others gathered in stairwells, arguing whether they should go up or down. Laurel tried to yell for them to follow her, but she gulped in a chestful of smoky air and began coughing uncontrollably.

“Faeries! This way!” David’s voice rang through the murk like a lighthouse in fog. He was standing tall, seemingly heedless of the dark clouds that swirled madly round him and Laurel suppressed a gasp; the smoke was being repelled by Excalibur’s magic. The layer of clear air that surrounded him couldn’t have been thicker than an eyelash, but the air he inhaled was clean, and he shouted again. “To the dining hall! They’re opening the skylights!”

At first, the faeries crowded on the stairs seemed paralysed by indecision, and Laurel realised they were standing there, holding their breath against the smoke, wondering whether they should follow David’s orders.

Because he’s human.

Then a Mixer Laurel didn’t recognise began pushing his way down through the crowd in David’s direction. For a moment Laurel’s eyes widened and she wondered if he was about to pick a fight. But he simply stood in front of David for a moment, then nodded, and ducked down to enter the smoky hallway that led to the dining hall. The other faeries finally seemed to get the message, and slowly, so painfully slowly, flowed into the hallway, heading toward the dining hall, crouched low so they could breathe.

But not everyone was following. A handsome young faerie was fighting through the crowd to go the other way. He had placed a foot on the bottom step when someone called out from beneath the smoke, “Galen, stop!”

Galen paused.

Something dark was pouring very slowly down the stairwell. For a moment Laurel thought it was oil, but then she realised it was tinged red and had a strange wispy quality to it – not unlike the smoke gathering all around them. But it wasn’t like the sleeping gas at the gateways, which had expanded and risen into the air; this mist was heavy and crept across the ground, like slow-moving dry-ice vapour, filling each step like sludge before a stream broke free and poured down onto the next step.

Galen’s mouth tightened. “There are still fae upstairs,” he called. “I have to warn them.” And without another delay, he continued up the steps.

The instant the red, creeping smoke touched his foot, Galen staggered and fell, his face going blank, his limbs convulsing. As he landed on the stairs, the deep red mist swirled out round him. Even through the hazy air, from three metres away, Laurel knew he was dead.

Others saw it too; there were several shrieks as fae fled the creeping mist – some running straight toward the burning exits.

“Stop, stop!” Yeardley’s voice was muffled in the choking smoke. “We must stop panicking,” he pleaded. “The skylights are open in the dining hall; everyone get to the dining hall!”

“Galen was right; some of the staff is still upstairs! Can’t we do something?” one of the lingering faeries asked.

Yeardley looked at the menacing gas pouring down both stairways that led to the upper floors. “Goddess help them,” he said weakly.

At last, most of the faeries made for the dining hall, but a few remained stubbornly looking up the stairs. As Laurel watched, the reddish mist spilled over the landing above them, cut into long tendrils by the ornate rails, flowing downwards like an oily waterfall.

“Look out!” Laurel shouted, pulling Tamani and Chelsea backwards with her, barely missing the thin streams of mist that fell in the pattern of prison bars.

Not everyone was quick enough, and scarlet waves poured over them like rivulets of sand; without a sound, they fell where they stood.

“Let’s go!” Tamani said, pulling at Laurel’s hand. She wanted to resist him – to pick up the fallen faeries, to carry them to safety. But Tamani’s hand was firm in hers and she let him draw her backwards.

In the dining hall, Yeardley was directing the students to line the bottom of the doors with wet cloths. Those in the bucket brigade who had escaped the deadly red poison were emptying buckets of water right onto the doors, soaking the wood. Thanks to the large skylights, now open to the dim evening sky, the smoke was higher here, and Laurel could stand up straight and still breathe. She looked over at Chelsea, whose face and clothes were blackened; Laurel assumed hers were the same. Glancing round, she was shocked at how few faeries were present, and even more shocked at how few were conscious. They’d been treating the injured here anyway, but now the injured were joined by dozens who had fainted from the smoke.