“We don’t have time for this,” Gill said. “Clear the rubble, Carmine.”

Carmine made an exasperated sound. Then she smiled. “Bye, Velvet.”

A pile of stones blocking the cave flew at Velvet. She lifted her arms to cover her face just before the wall slammed into her, knocking her backward and half burying her. She was dazed for a moment, watching Octavia fighting the other Huntsmen, her weapon moving too fast to see, as rocks continued to fly from the diminishing pile of rubble. A beam of moonlight cut through the darkness. Carmine was breaking through.

Then something glittered in front of Velvet. She pulled herself from the rocks covering her and scooped it up. It was a red crystal.

It was Dust.

If this cave had been closed off before the Great War because of an avalanche—if the cave was too unstable to rescue those trapped miners—that meant the Dust had never been removed. This might be the last small repository of Dust in Vacuo.

“Octavia!” Velvet called. “Fire!” She held up the Dust crystal.

Octavia turned and saw what Velvet was holding. Even without Fox’s teamspeak, she knew instantly what Velvet was thinking. Now they had a way to stop Gill from reaching the battlefield, cutting off her ability to send Aura to the troops there.

It took Carmine a little longer to catch on.

“No!” she said as Octavia waved her kris and sent a torrent of fire from the blade toward her—then past her.

And into a glittering fire Dust deposit in the wall. The blast ignited the whole vein.

The tunnel was very bright and very hot for a moment, before everything went dark.

- RWBY: Before the Dawn, Chapter 18