Ambrose ran down the Corridors of Time, guided by his Ghost, hunted by the Axis Vex.

He had not missed the sterile whiteness of eternity, nor the echoing silence that swallowed every sound he made. He disliked the way light behaved in this place, devoid of color, as if something had gone wrong with his eyes. Each courtyard was different this time. Some had the same tree he had seen before, floating in its chunk of disembodied soil. But some had huge geometric shapes made of stone. Some had remnants of the graceful fungus trees that used to cover Mercury. Some had ruins of buildings on Earth. Every door was open in every courtyard. Ambrose navigated by a map Osiris had given him.

Osiris had spent hours studying Saint-14's Ghost. He had taken it through the Sundial while Ambrose watched from outside. Sometimes, beneath the spinning pylons, there had been multiple copies of Osiris. Sometimes there had been only invading Vex. Sometimes there was something else, a half-seen horror of blackness, formless squirming shapes, and whispers. And once there had been a black pyramid with green lights along its base.

By the time Osiris emerged, Ambrose had stopped watching the Sundial. If he gazed into it any longer, he'd be too terrified to set foot inside.

"I have found a path, I think," Osiris said. "Sagira is sending it to your Ghost. Look for these symbols and pass through those doors. It should take you to Saint-14's last hours. I tried to go, myself, but the Vex have built safeguards against me. It will take time to dismantle them. But you … they cannot calculate your actions. Be unpredictable."

"Yes sir," Ambrose had replied, wondering how to be unpredictable when following a set path. "I'll do my best. How do I return, afterward?"

"I will fetch you once the timelines change," said Osiris.

Now Ambrose was running, following Peach's directions. "Next up is a squiggly thing like two snakes."

"Over there?" Ambrose panted, ducking behind a pillar as a hail of bullets pared the face of the stone away.

"Yes, across the center," Peach confirmed. She healed a bullet scratch in his left arm. "Blast these Vex. Why can't they leave us alone?"

Ambrose summoned a Light grenade and threw it into the middle of a squad of goblins stalking toward him. The explosion blew them to pieces and tore a respectable crater in the floor.

This provided enough breathing space for Ambrose to dash for the next doorway. Once through, he was back in the echoing whiteness between worlds, running down his own timeline toward a pyramid-shaped door in the distance.

"What next?" he called to Peach.

"That was the last symbol," she replied in his head. "Next should be-"

They passed through the pyramid and emerged inside the Infinite Forest. Geometric shapes crackled around them like lightning as the simulation tried to account for their sudden presence. A landscape sprang into being around them, chunks loading in. Dark rocks, eroded soil, a cold sky with a dark, dead sun.

"Oh look," Ambrose panted. "The simulated bad future that the Vex are so bloody fond of."

"I didn't like it the first time we were here," Peach muttered. "I'm detecting movement over there. I think it's Saint-14. I'm picking up Geppetto's tag. Wow, it's really strange seeing him alive."

Ambrose paused a moment to reload his rifle, then picked his way toward the other Guardian, keeping under cover of tumbled boulders and toppled pillars. His heart pounded with fresh adrenaline. He'd reached the doomed Titan, but was he in time?

He rounded a corner and saw Saint, also sheltering behind a boulder, his back to Ambrose. He was reloading the Perfect Paradox shotgun. Everywhere were scattered the limbs and bodies of robots, the white milk of their lifeblood staining the soil. Ambrose could almost smell the chemical stench of it through his helmet.

"Hoi there, Saint!" he called, raising a hand.

The Titan jerked around, raising his rifle by reflex. Then he lowered it, straightening. His relieved grin was evident in his voice. "Guardian Ambrose? What a surprise to see you here."

Ambrose dashed forward and joined him in his hiding place. More Vex were amassing on the next hilltop, but had not yet stormed the Guardian's hiding place.

Saint shook his hand vigorously. "You are most welcome! This battle is nearly over, win or lose. See that hydra up there? Is called the Martyr Mind. It drained my Light." He held out a hand as if trying to summon a grenade, but nothing happened. "I was preparing to send my Ghost away."

"Don't do that," Ambrose said. "I found him on the other side. He won't make it."

"Right." Saint bowed his head for a moment, as if listening to the protests of his friend. "Well then. You and I will fight together. The Lord sent you in the nick of time, eh?"

"Actually, it was Osiris," Ambrose said.

Saint-14 guffawed and slapped his thigh. "Osiris! He always cause trouble for me. Tell him I owe him broken nose for running to Infinite Forest." He lifted his shotgun and ratcheted a shell. "Let us fight, friend. Throw grenade for me. Lots of grenade."

"All I can manage," Ambrose promised.