The Moon kept no days, so Urahara invented them.
He did it the second week, when the physicists began snapping at each other over nothing and a woman from CERN cried in the centrifuge room where she thought no one could hear. The next shift there was a sky. Not a real one, a field laid over the great glass ceilings that ran a dawn up one side of the base and a dusk down the other, on a cycle stolen from a city none of them would name aloud.
There was a smell of morning in the mess at the start of a shift and a smell of rain at the end of it. The woman from CERN stopped crying. Nobody thanked Urahara, because nobody had caught him doing it, which Megumi was beginning to understand was the way the man preferred nearly everything.
"You can't fix homesickness with a lighting rig," Megumi told him, because he was eleven and it was his job to be unimpressed.
"No," Urahara agreed, not looking up from the thing he was building, which today appeared to be a clock with far too many hands. "You can't. But you can take the edge off it while people fix themselves. That's most of what medicine is, you know. Buying the patient time to get better on their own."
He fitted a hand to the clock; it began, immediately, to run backwards, and he made a small satisfied noise. "The trick is never letting them see the rig. A kindness you get caught doing turns into a debt. Do enough of them in the dark and people just decide the world is a bit warmer than they thought." He glanced up, and the grin was there, guileless as a shopfront. "And then they'd walk into a reactor for you. Purely hypothetically."
Megumi decided not to think too hard about that one.
His training happened in the shadow-hall, a long black room the engineer had built to Aizen's specification before he left, no light, no edges, walls that drank sound, a floor of something that took a shikigami's weight without echoing. Aizen had trained him here for three years. Now Aizen was four light-years away, and the hall was Megumi's alone, and he had discovered that he hated it.
He set his hands. He breathed the way he had been taught, gathering the cold that lived under his ribs. From the dark at his feet the shadows peeled up into two shapes, the Divine Dogs, white and black, snarling at nothing, at everything, at him. He held them. He reached, the way Aizen had shown him, past the dogs, past the toad, past the nue with its folded wings, down into the deep water of the technique where the big ones waited, and he tried, as he tried most days, to call up the elephant.
The water shifted. Something vast turned over in it, far down, and did not rise.
He held the reach until his nose bled, and then a little past that, and then the dogs frayed at the edges and he had to let them go before he lost them for good. He sat down hard on the drinking-sound floor with the taste of copper in his throat and his hands shaking, and he was glad, fiercely glad, that the hall ate echoes, so that no one heard the noise he made.
"You're reaching too far down."
He hadn't heard the door. Of course he hadn't. Urahara stood just inside it, out of the black by some trick, holding two cups.
"Get out," Megumi said.
"Mm. In a minute." Urahara sat, uninvited, cross-legged, and set a cup by Megumi's knee. Chocolate again. Always chocolate. "You're going down after the big ones because your father did, and your father does everything from the bottom up, most cursed energy in recorded history, he can afford to. You can't. Not yet." He sipped.
"You've been trying to lift the whole ocean to reach the thing at the bottom of it. Stop. Grow the small ones instead. A dog you can actually keep. A toad that doesn't dissolve when you sneeze. Get the shallow water so strong it does the work for you, and one day the deep water will come up on its own, because you'll finally be worth rising for." He shrugged. "That's a guess. I don't have your technique. I don't have any technique worth the name. But I've watched a great many people fail at a great many things, and they nearly all fail the same way, they reach for the end instead of building the middle."
Megumi looked at the cup and did not touch it. "Why do you care whether I get stronger?"
It was the wrong question, or the right one, he watched Urahara decide which. The man's face did something complicated and brief, and then folded back into the shopkeeper, and Megumi, who had grown up among people who wore their faces like coats, filed the flicker away without knowing yet what it meant.
"Because it's my job to look after you," Urahara said, which was true, and not an answer, and he plainly knew Megumi knew it. "Drink your chocolate. Grow your dog. Insult a physicist. You'll feel better." He rose, clogs whispering on the sound-eating floor. "You're not the loneliest thing on this Moon, you know. You just have the worst manners about it."
He was gone before Megumi could ask what the loneliest thing was.
He found out later, and by accident, which was the only way anyone found anything out about Urahara.
He had gone up to the gallery over the accelerator, his room, in every way that mattered, and the shopkeeper was already there, at the rail, and he was not smiling. On the console at his elbow the single light Megumi had watched blink for a month was no longer blinking. It was steady. And beside it a second light had woken, and a third.
"What are they," Megumi said.
Urahara didn't startle. He never startled. "Questions," he said. "I told you, weeks ago. Something out in the dark, asking the Moon questions." He turned one of the lights with a fingertip and it threw a lattice of numbers across the glass, and Megumi understood none of it except that it was a map, and the Moon was on it, and something on the Earth was drawing very careful lines toward the Moon. "For a month it was one voice. Idle. A telescope with a grudge. Somebody clever on the ground who'd noticed the sky was the wrong shape here and couldn't let it go." He tapped the second light. "Now it's two voices, and they've started talking to each other. And when two clever things that shouldn't know about each other suddenly do," he closed the fan he hadn't been holding a moment ago, "it usually means a third clever thing introduced them on purpose."
"Should we tell my father?"
"Your father," Urahara said, "left me a Moon and a boy and a great many instructions, and not one of them was panic." He said it lightly, and Megumi almost believed it, and then the man looked back down at the map with its careful, converging lines, and for just a moment the shopfront was dark and there was only the thing behind the counter, taking inventory.
"No. We don't tell him yet. We watch. We let them get close enough to be interesting and not close enough to be a problem. And when they knock," the grin came back, and this time it did not reach his eyes at all, "we'll be the warmest, most helpful hosts they've ever met. Right up until we aren't."
Below them the Hōgyoku turned and turned, throwing its slow petals of light, and on the console the three steady stars of the watching Earth burned on, and the boy and the shopkeeper stood at the rail of the largest machine ever built and watched their home planet begin, very patiently, to find them.
"Drink your chocolate," Urahara said. "It's a long way off yet."
It was not, as it turned out, as far off as he thought.