The underhall was not dark. It was lit in a brilliant rainbow of colours, as if the sun shone directly in the great half-rose window. And on the window, the Emperor Aetius marched across window after window, making laws, ordering the execution of the former emperor’s family, winning the great battle of Chaluns, living out his life as a monk.

The emperor himself wore his armour of gilded steel. He had his ghiavarina in his hand, and his helmet on his head.

Ariosto, in the hall above, gave a raucous scream.

“You’re sure?” Mortirmir asked.

Gabriel looked at him and gave an easy smile.

Cully stepped out of the ranks. “Cap’n?” he asked.

“Cully?”

“I’d like to stand wi’ ye, if you don’t mind.” Cully shrugged.

Bad Tom gave a fractional nod.

Gabriel nodded back. “Thanks, Cully.”

The two of them walked down into the sun-drenched room. It was warm. The flood of colour was supernatural.

“Cap’n?” Cully asked.

“Yes?” Gabriel asked. He was trying to rein in his impatience to get it done.

“Look there,” Cully said. He was pointing at the central figure of Aetius.

Gabriel shrugged. “Beautiful,” he said in a meaningless way. He walked forward toward the central panel, and the keyhole, and Cully could see his hands were shaking.

Cully took his great bow off his shoulder and checked the string, and then drew a single heavy arrow from his belt and put it on the string.

“Good luck, Cap’n,” he said.

Gabriel looked back. He looked up, at the waiting troops, and then he looked at the gate.

The light grew, if anything, brighter.

There was a sound, like a bell ringing, a perfect note, like silver or crystal. The sound seemed to fill the underhall.

Morgon raised his shields. So did Petrarcha and Tancreda and twenty other magisters.

Gabriel went inside his palace, where the simulacrum of his tutor stood on her pedestal.

“Ave, Prudentia,” Gabriel said.

“Ave,” she answered. “You stand on the threshold.” She smiled, her white marble lips arching. “I hear the music of the spheres.”

He nodded. He had prepared everything he could, the way he had for his tutor’s examinations; shields hung, ready to use, and spears of light, clouds of darkness, balls of fire, a sword he’d designed himself, and some subtle, complicated stuff he’d decoded from Al Rashidi’s fading mind.

He took a single shield of pure green and a living buckler of gold; perhaps the densest protective spell he’d ever cast.

“Ready?” he asked.

Prudentia smiled. “For this, you were born,” she said.

He started. “What? You can’t know that!”

Prudentia smiled. “Ask me no questions, and I’ll tell you no lies.”

“Damn it, Pru! This is not the time!” he said, but inside he felt as if a dam had burst.

Would you be lord of all the worlds?