The night air of the Roman countryside was warm and smelled of dry grass and rosemary and the distant cookfires of the city.  Above them the stars were bright and Rome glowed against the horizon — not a single light but a general luminescence, the accumulated glow of a city of a million souls going about the business of their evening.  Even from here Merlin could hear it, a low continuous murmur that never quite resolved into individual sounds.  He had forgotten how alive Rome was, even at night.  Especially at night.

He reached into his pocket.  The mouse looked up at him from his palm with the alert and slightly accusatory expression of a creature that has spent two days in a wizard's pocket crossing the channel and most of the continent and has opinions about this.

"Yes," Merlin agreed, "I know.  I am sorry about that."  He set the mouse carefully in the long grass and crouched down.  He whispered to it for a moment, his long fingers cupped gently around it.  The mouse sat very still, listening with the focused attention it had learned was generally worth applying to whatever this particular human said to it.  When Merlin finished speaking he lifted his hand and the mouse sat a moment longer, then turned and disappeared into the grass with a businesslike rustle.  There was good Italian clover not far off.  It would find its way.

Merlin stood and turned to Yggdrasil who had been watching this exchange with her gold eyes half lidded. "The mouse," she said, in the tone of someone filing away a piece of information they find simultaneously baffling and faintly illuminating.

"He was a long way from home," Merlin said simply and turned to look at the city.

Yggdrasil lowered her great head beside him so that they were both regarding Rome from roughly the same vantage point, though what she saw with those ancient gold eyes and what Merlin saw with his were almost certainly very different things.  "The inlet is there," she said, indicating with the faintest tilt of her head toward the dark eastern wall where the aqueduct entered the city in its great arched channel.  "I can smell the water."

"You'll need to wait until the third hour of the night," Merlin said.  "The streets need to be quieter before you approach.  The inlet is outside the walls but there are sentries on the eastern gate and I don't want them raising an alarm before the sleep breath has reached them."

"And how will I know when it is the third hour?" she asked.

"Rome rings her bells," Merlin said.  "You'll hear them."

Yggdrasil regarded him.  "And you?  You are going in now?"

"I need time to get into position before you begin."  Merlin pulled his hood up over his head and checked within his robes — the small stone-encased sword sat in his pocket, the herbs for his visions, his pipe, the small pewter dish.  Everything present.  "Once the sleep breath starts moving through the aqueducts it will spread through the city faster than a man can walk.  I need to already be where I need to be when that happens."

"Where Mab is," said Yggdrasil.

"Where Mab is," Merlin confirmed.

A pause settled between them.  An owl called somewhere in the field behind them.  Yggdrasil's breath moved the grass in slow warm waves.  "When I begin," she said, "I will not be able to stop until it is done.  If you need more time than I can give you, I cannot help that.  If the city wakes before you are finished — "

"It won't come to that," Merlin said.

Another pause, longer.  "The mouse," Yggdrasil said again, and this time the word sat differently in her mouth, as if she were turning something over that she hadn't expected to find there.  She said nothing further.  She simply settled into the grass like a hillside deciding to become permanent and closed her gold eyes and Merlin understood he had been dismissed.

He turned toward Rome and walked.

The eastern gate of Rome was manned by four soldiers of the Palatine guard, their armor catching the torchlight in the lazy manner of men who had stood this post a thousand nights without incident and expected tonight to be the thousand and first.  Merlin approached along the road without hurrying, his hood up, his staff making its regular knock against the paving stones.  One of the guards stepped forward with a hand up.

Merlin lowered his hood slightly and let the power rise just enough to glow faintly amber in his eyes.  The guard's hand stayed up but the rest of him took a step back.  "State your business," the man said, with the admirable commitment to duty of someone whose body clearly wanted to be somewhere else entirely.

"I am a physician," Merlin said in Latin, which he spoke as fluently as he spoke everything else, "called for the Bishop Epiphanius who has taken unwell."  He pulled from within his robe a document — beautifully rendered on fresh vellum in an ecclesiastical hand, sealed with a wax impression that bore the mark of the bishop's office — and presented it to the guard with the bored efficiency of a man who has done this before.

The guard took the document, looked at it, held it at a slight angle to catch the torchlight better, and handed it back.  He had almost certainly not read it.  The seal had done its work.  "Pass," he said and stepped aside.

Merlin pulled his hood back up and walked through the gate into Rome.

He had prepared the document two nights ago on the rocky outcropping while Yggdrasil slept, conjuring the vellum and the ink and the seal from the materials he carried, working by the light of a small and carefully contained flame while the channel moved dark around him.  He had also prepared three further documents of varying authority for varying situations.  A wizard, he had long believed, should be able to fight his way out of most situations but should prefer to talk his way out where possible and should always have the paperwork.

Inside the walls Rome was everything he remembered and nothing like he remembered simultaneously.  The bones of the city were the same — the great arterial roads running straight and wide between the densely packed insulae, the smell of bread and garum and sewage and incense that was Rome's singular perfume, the way sound behaved differently here than anywhere else, bouncing off stone and marble and coming back changed.  But the city was older now, layered with the additions of generations, the old buildings patched and built over and built over again until the Rome of Caesar was somewhere underneath the Rome of Glycerius like a palimpsest.  Torches burned at intervals along the main roads.  The side streets were dark.

Merlin moved through the city with the purposeful unhurried pace of a man who belongs exactly where he is.  He had learned long ago that the most effective form of concealment in a city was not invisibility but certainty — a man who moves as if he knows where he is going and has every right to go there is almost entirely invisible to casual observation.  He kept to the main roads where the torchlight gave him clear vision and the foot traffic, still considerable at this hour, gave him cover.

The bishop's residence was in the shadow of the Palatine Hill, a substantial building of white stone set back from a colonnaded street.  Merlin had seen it in his visions and found it without difficulty.  He did not go to the front entrance.  He walked the perimeter of the building once, reading it — the placement of guards, the lit and unlit windows, the side entrance used by servants, the small garden at the rear with its fig tree and its well and its convenient shadows.  He counted nine guards in total, stationed with the regular spacing of a security arrangement that had been designed to look serious without being particularly serious.  Epiphanius — or rather, Mab wearing Epiphanius — clearly did not expect a direct assault.  Why would she?  She was a bishop in the most powerful city in the world surrounded by the soldiers of an empire.

What she was expecting was Merlin.  He had no doubt about that.  The wink from inside his vision had been an invitation as much as a taunt.  She had set the table and she was waiting for him to sit down.

Merlin settled into the shadows of the garden beneath the fig tree, folded himself crosslegged onto the ground and waited.  Above him Rome murmured and flickered.  Somewhere in the city a man was singing, something low and repetitive, the kind of song that exists only to fill silence.  Merlin listened to it and found himself thinking of his mother, which surprised him.  He rarely allowed himself that.  He put the thought away carefully and listened to Rome instead and watched the windows of the bishop's residence for the movement of a shadow that moved differently than the others.

The bells rang the third hour.

Merlin rose, brushed the Italian dust from his robes and moved to a position beside the garden wall where he had a clear line of sight to both the main entrance of the residence and the street beyond.  He settled his breathing.  He pressed the flat of his palm against the paving stone beneath him and sent his awareness down through it, down through the stone and the soil beneath the stone, reaching for the water.

He found it almost immediately — the vast cool network of the aqueduct running beneath the city like a second circulatory system, patient and constant, carrying its cargo through the stone arteries under every road and building.  He held his awareness there and waited.

It began as the faintest change in the quality of the water.  Not a smell exactly, not through stone, but a difference — something moving through the channel that was not water.  Then another.  Then it was everywhere at once, spreading through the network the way dye spreads through cloth, following every channel and branch and tributary simultaneously, rising through every vent and grate and outlet in the city in thin pale wisps of vapor that meant nothing to a man hurrying home and everything to a man paying attention.

Yggdrasil had begun.

Merlin watched a torch-bearer on the street beyond the garden wall slow his pace.  Then slow it further.  Then sit down quite deliberately on the kerb as if he had just remembered somewhere very comfortable he needed to be.  The torch listed sideways in his relaxing grip.  A woman crossing the street stopped walking, looked around her with a pleasantly confused expression and then simply sat down where she was.  A soldier at the corner of the bishop's residence leaned his spear against the wall, put his back to the stone and slid gently to a sitting position, his chin dropping to his chest.  Then the second soldier.  Then the third.

Rome was going to sleep.

Not all at once — it was more like a tide going out, the energy of the city ebbing gradually from the edges inward, the sounds of it softening, the lights of it stilling as the hands tending them relaxed.  The singing man somewhere in the city sang two more phrases and then stopped mid-word.  The great murmur of Rome that never fully ceased even at the deepest hour of the night diminished and dimmed and then was simply gone, replaced by a silence so complete and so unlikely that Merlin felt the hair on his arms rise at it.

A city of a million people, asleep.

He gave it another few minutes, watching the residence.  The last of the visible guards had gone down.  The windows were still.  He straightened his robes, tucked his beard into his collar with the care of a man who had learned certain lessons about beards and open flames, and walked toward the entrance of the bishop's residence.

The door was unlocked.  He hadn't expected anything else.  He pushed it open and stepped inside.

The entrance hall was grand in the Roman fashion — marble floors, frescoed walls, oil lamps burning in their niches casting a warm amber light over a floor scattered with the sleeping forms of servants and attendants, draped where they had fallen like figures in a tapestry depicting the aftermath of something.  Merlin stepped between them carefully, moving deeper into the residence.  He passed through two further rooms, both similarly occupied by the sleeping, until he reached the large receiving room at the heart of the building.

She was sitting in the bishop's chair at the far end of the room.

Not Epiphanius.  She had shed that face entirely.  Mab sat in the bishop's chair in her own form — pale as winter, raven haired, her eyes the color of deep ice, dressed in robes of black and silver that moved slightly as if stirred by a wind that wasn't present in the room.  Her hands were folded in her lap.  She looked entirely unsurprised.

She looked, in fact, as if she had been waiting quite some time and found the wait only mildly tedious.

She looked at Merlin standing in the doorway of her sleeping city and allowed a small and very old smile to cross her face.

"Myyrrddryn," she said, and his name in her mouth was nothing like it was in Aelphaba's mouth or Yggdrasil's.  It was something else entirely.  Something that knew him from before he knew himself.  "You are late," she said.  "I expected you a fortnight ago."

Merlin stepped into the room.  "I was delayed," he said.

"Yes," said Mab, and the smile didn't change, "you were."  And in the way she said it Merlin understood that she knew exactly what had delayed him and that Nimue's role in that delay had not been accidental at all.

The door swung shut behind him of its own accord.

Merlin stood in the lamplit room in the center of a sleeping city with Mab watching him from the bishop's chair and felt the full weight of however many centuries of patience and planning had led to this precise moment settle into the room around them like a third presence.