The woman and her dog stepped onto the path.

And disappeared.

Luce gasped, but then Daniel pointed behind her, to the other side of the Foundation’s lawn. She spun around.

Forty feet away, where the pebble path ended, and the modern sidewalk picked up once again, the woman and her dog reappeared. The dog yapped hysterically, but the woman walked on as if nothing had disturbed her morning routine.

It was strange, Luce realized, that the angels’ whole mission was to keep her life that way. So that nothing happened to erase this woman’s world, so that she never even noticed how much danger she’d been in.

But while the people on the street might not have noticed Luce or the angels, they certainly did notice the sky. The woman with the dog kept glancing up at it worriedly, and most of the people leaving their houses wore slickers and carried umbrellas.

“Is it going to rain?” Luce had flown through pockets of rain with Daniel, warm showers that left them refreshed and exhilarated . . . but this sky was ominous, nearly black.

“No,” Dee said. “It isn’t going to rain. That’s the Scale.”

“What?” Luce’s head shot up. She squinted at the sky, horrified when it shifted and pitched. Storm clouds didn’t move like that.

“The sky is dark with their wings.” Arriane shuddered. “And their cloaks.”

No.

Luce stared at the sky until it began to make sense.

With a feeling akin to vertigo, she made out an undulating mass of blue-gray wings. They were smeared across the sky, thick as a coat of paint, blocking out the rising sun. The beats of the short brutish wings buzzed like a swarm of hornets. Her heart clenched as she tried to count them. It was impossible. How many hundreds hovered in the multitude above?

“We’re under siege,” Daniel said.

“They’re so close,” Luce said, flinching as the sky roiled. “Can they see us?”

“Not exactly, but they know we’re here,” Dee said nonchalantly as a small group of Scale swooped lower, low enough for them to see their shriveled, bloodthirsty faces. Cold eyes trolled the space where Luce and the others gathered, but when it came to the Patina, Scale seemed to be about as blind as the Outcasts.

“My Patina surrounds us, the way a tea cozy surrounds a pot, forming a protective barrier. The Scale can’t see or travel through it.” She managed a smile at Luce. “It only answers to the ringing of a certain kind of soul, one innocent of its own potential.” Daniel’s wings pulsed beside her. “They’re gathering more brethren all the time. We need some way to get out of here, and we need to hurry.”

“I do not intend to be bound in one of their broke-neck burkas,” Dee said. “No one takes me in my own house!”

“I like the way she talks,” Annabelle said sideways to Luce.

“Follow me!” Dee shouted, breaking into a run along a gated alley. They jogged behind her through an unexpected pumpkin patch, around an ornate and dilapi-dated gazebo into an expansive and lushly green backyard.

Roland’s chin tilted toward the sky. It was darker now, denser with wings.

“What’s the plan?”

“Well, for starters”—Dee wandered over to stand under a mottled oak tree in the center of the garden—“the library must be destroyed.”

Luce gasped. “Why?”

“Simple mechanics. This Patina has always encompassed the library, so with the library it must stay. In order to move past the Scale, we’ll have to open the Patina, thereby exposing the Foundation, and I do not intend to leave it for their indiscriminating wings to root through.” Her hand patted Luce’s stricken face. “Don’t worry, dear, I’ve already donated the valuable volumes in the collection—to the Vatican, mostly, though some went to the Huntington, and to a little unsuspecting town in Ar-kansas. No one will miss this place. I’m the last librarian here, and frankly, I don’t plan to return after this mission.”

“I still don’t understand how we get past them.” Daniel’s gaze stayed fixed on the swirling blue-black sky.

“I will have to produce a second Patina, surrounding only our bodies, guaranteeing us safe passage. Then I will open this one and let the Scale flow in.”

“I think I’m smelling what you’re cooking,” Arriane said, climbing up a branch like a monkey to sit nestled in the oak tree.

“The Foundation will be sacrificed”—Dee frowned—

“but at least the Scale will make nice kindling.”

“Hold on, how does the library get sacrificed?” Roland crossed his arms over his chest and looked down at Dee.

“I was hoping you could help with that, Roland,” Dee said, eyes twinkling. “You’re rather good at starting fires, aren’t you?”

Roland raised his eyebrows, but Dee had already turned around. Facing the tree trunk, she reached for a knot in its bark, pulled it like a secret doorknob, and opened the trunk to a hollowed chamber. Inside, the wood was polished, the chamber about the size of a small locker. Dee’s arm dipped in and pulled out a long golden key.

“That’s how you open the Patina?” Luce asked, surprised that it required so physical a key.

“Well, this is how I unlock it so that it can be manipulated for our needs.”

“When you open it, if there’s a fire,” Luce said, remembering the way the woman walking her dog blinked out of existence for a moment while she crossed the Foundation’s front lawn, “what will happen to the houses, to the people on the street?”

“Funny thing about the Patina,” Dee said, kneeling down and rooting around in the garden for something.

“The way it sits on the border between realities past and present, we can be here, and not here, in the present, and also elsewhere. It’s a place where everything we imagine about time and space comes together materially.” She lifted up the fronds of an oversized fern, then dug in the dirt with her hands. “No mortals outside will be affected, but if the Scale are as ravenous as we all know they are, as soon as I open this Patina, they’ll swoop right towards us. For one tense moment, they will join us in the elsewhere reality when the Foundation Library stood on this street.”

“And we’ll fly out, enclosed in the second Patina,” Daniel guessed.

“Precisely,” Dee said. “Then we have only to close this one around them. Just as they can’t get in now, they won’t be able to get out then. And while we soar on safely to lovely, ancient Avignon, the library will go up in smoke, with the Scale trapped inside.”

“It’s brilliant,” Daniel said. “The Scale will still technically be alive, so our action won’t tip the Heavenly balance, but they’ll be—”

“Burn marks of the past, sealed off, out of our way.

Right. Everybody on board?” Dee’s face lit up. “Ah, there it is!”

As Luce and the angels stood over her, Dee brushed the dirt off a collared hole that had been buried in the garden. She closed her eyes, held the key close to her heart, and whispered a blessing:

“Light surround us, love enfold us, shelter us, Patina, from the evil that must come.”

Carefully, she fit the key into the lock. Her wrist shook with the force required to turn the key, but finally, it creaked a quarter turn to the right. Dee exhaled heavily and rose to her feet, wiping her hands on her skirt.

“Here we go.”

She raised her arms above her head and then, very slowly, very purposefully, brought them down toward her heart. Luce waited for the earth to shift, for anything to happen, but for a moment, nothing seemed to have changed.

Then, as the space around them grew pin-drop quiet, Luce heard an almost inaudible swishing sound, like bare palms being rubbed together. The air seemed to slightly warp, making everything—the brown house, the row of Viennese townhouses surrounding it, even the blue wings of the Scale above—waver. Colors bent, melted. It was like standing inside the cloudy haze over flowing gaso-line.

As before, Luce could both see and not see the Patina. Its amorphous boundary was visible one moment—

with the iridescent transparency of a soap bubble—then it disappeared. But she could feel it molding around the small space in the garden where she and the others stood, emanating warmth and the feeling of being embraced by something powerfully protective.

No one spoke, silenced by the wonderment of Dee.

Luce studied the old woman, who was humming so intensely she almost seemed to buzz. Luce was surprised when she sensed the inner Patina was complete. Something that hadn’t felt whole a moment before now did.

Dee nodded, her hands at her heart as if in prayer. “We are in the Patina within the Patina. We are in the heart of safety and security. When I open the outer rim to the Scale, trust that security and remain calm. No harm can come to you.”

She whispered the words again— Light surround us, love enfold us, shelter us, Patina, from the evil that must come—and Luce found herself murmuring along. Daniel’s voice chimed in, too.

Then there was a hole, like a gust of cold air entering a warm room. They shuffled closer together, wings pressing up against each other, Luce in the center. They watched the shifting sky.

A savage shriek came from high above, and a thousand others joined in. The Scale could see it now.

They swarmed toward the hole.

The opening was mostly invisible to Luce, but it must have been directly over the chimney of the brown house.

That was where the Scale headed, like winged ants at-tacking a drop of fallen jam. They thudded to the roof, to the grass, to the eaves of the house. Their cloaks rippled with the impact of rough landings. Their eyes trolled the property—both sensing and not sensing Luce, Dee, and the angels.

Luce held her breath, did not make a sound.

The Scale kept coming. Soon the yard bristled with their stiff blue wings. They surrounded Dee’s inner Patina, casting glances hungry as wolves’ directly at the place where the prey they sought were hiding. But the Scale could not see the angels, the girl, and the transeternal safe inside.

“Where are they?” one of them snarled, his cloak tangling in a sea of blue wings as he pushed through the crowd of his brethren. “They’re here somewhere.”

“Prepare to fly fast and hard to Avignon,” Dee whispered, standing stiffly as a Scale angel with a birthmark splashed across his face leaned in near the limits of their Patina and sniffed like a pig seeking slop.

Arriane’s wings were trembling and Luce knew she was thinking of what the Scale had done to her. Luce reached for her friend’s hand.

“Roland, how about that mighty conflagration?” Daniel said through pursed lips.

“You got it.” Roland interlaced his fingers and furrowed his brow, then gave one hard glance at the brown house. There was a great blast, like a detonating bomb, and the Foundation Library exploded. Scale were sent shrieking into the Patina sky, their cloaks engulfed in fin-gerlike flames.

Roland waved his hand, and the hole where the library had stood became a volcano spewing flames and lava rivers through the lawn. The oak tree caught fire.