She had been running for four days now, a harum-scarum tumbling flight through passages and tunnels. She was hungry, and exhausted, and more tired than a body could stand, and each successive door was proving harder to open. After four days of flight, she had found a hiding place, a tiny stone burrow, under the world, where she would be safe, or so she prayed, and at last she slept.

Mr. Croup had hired Ross at the last Floating Market, which had been held in Westminster Abbey. "Think of him," he told Mr. Vandemar, "as a canary."

"Sings?" asked Mr. Vandemar.

"I doubt it; I sincerely and utterly doubt it." Mr. Croup ran a hand through his lank orange hair. "No, my fine friend, I was thinking metaphorically—more along the lines of the birds they take down mines." Mr. Vandemar nodded, comprehension dawning slowly: yes, a canary. Mr. Ross had no other resemblance to a canary. He was huge—almost as big as Mr. Vandemar—and extremely grubby, and quite hairless, and he said very little, although he had made a point of telling each of them that he liked to kill things, and he was good at it; and this amused Mr. Croup and Mr. Vandemar. But he was a canary, and he never knew it. So Mr. Ross went first, in his filthy T-shirt and his crusted blue-jeans, and Croup and Vandemar walked behind him, in their elegant black suits.

There are four simple ways for the observant to tell Mr. Croup and Mr. Vandemar apart: first, Mr. Vandemar is two and a half heads taller than Mr. Croup; second, Mr. Croup has eyes of a faded china blue, while Mr. Vandemar's eyes are brown; third, while Mr. Vandemar fashioned the rings he wears on his right hand out of the skulls of four ravens, Mr. Croup has no obvious jewelery; fourth, Mr. Croup likes words, while Mr. Vandemar is always hungry. Also, they look nothing at all alike.

A rustle in the tunnel darkness; Mr. Vandemar's knife was in his hand, and then it was no longer in his hand, and it was quivering gently almost thirty feet away. He walked over to his knife and picked it up by the hilt. There was a gray rat impaled on the blade, its mouth opening and closing impotently as the life fled. He crushed its skull between finger and thumb.

"Now, there's one rat that won't be telling any more tales," said Mr. Croup. He chuckled at his own joke. Mr. Vandemar did not respond. "Rat. Tales. Get it?"

Mr. Vandemar pulled the rat from the blade and began to munch on it, thoughtfully, head first. Mr. Croup slapped it out of his hands. "Stop that," he said. Mr. Vandemar put his knife away, a little sullenly. "Buck up," hissed Mr. Croup, encouragingly. "There will always be another rat. Now: onward. Things to do. People to damage."

Three years in London had not changed Richard, although it had changed the way he perceived the city. Richard had originally imagined London as a gray city, even a black city, from pictures he had seen, and he was surprised to find it filled with color. It was a city of red brick and white stone, red buses and large black taxis, bright red mailboxes and green grassy parks and cemeteries.

It was a city in which the very old and the awkwardly new jostled each other, not uncomfortably, but without respect; a city of shops and offices and restaurants and homes, of parks and churches, of ignored monuments and remarkably unpalatial palaces; a city of hundreds of districts with strange names – Crouch End, Chalk Farm, Earl's Court, Marble Arch – and oddly distinct identities; a noisy, dirty, cheerful, troubled city, which fed on tourists, needed them as it despised them, in which the average speed of transportation through the city had not increased in three hundred years, following five hundred years of fitful road-widening and unskillful compromises between the needs of traffic, whether horse-drawn, or, more recently, motorized, and the needs of pedestrians; a city inhabited by and teeming with people of every color and manner and kind.

When he had first arrived, he had found London huge, odd, fundamentally incomprehensible, with only the Tube map, that elegant multicolored topographical display of underground railway lines and stations, giving it any semblance of order. Gradually he realized that the Tube map was a handy fiction that made life easier but bore no resemblance to the reality of the shape of the city above. It was like belonging to a political party, he thought once, proudly, and then, having tried to explain the resemblance between the Tube map and politics, at a party, to a cluster of bewildered strangers, he had decided in the future to leave political comment to others.

He continued, slowly, by a process of osmosis and white knowledge (which is like white noise, only more useful), to comprehend the city, a process that accelerated when he realized that the actual City of London itself was no bigger than a square mile, stretching from Aldgate in the east to Fleet Street and the law courts of the Old Bailey in the west, a tiny municipality, now home to London's financial institutions, and that that was where it had all begun.

Two thousand years before, London had been a little Celtic village on the north shore of the Thames, which the Romans had encountered, then settled in. London had grown, slowly, until, roughly a thousand years later, it met the tiny Royal City of Westminster immediately to the west, and, once London Bridge had been built, London touched the town of Southwark directly across the river; and it continued to grow, fields and woods and marshland slowly vanishing beneath the flourishing town, and it continued to expand, encountering other little villages and hamlets as it grew, like Whitechapel and Dept-ford to the east, Hammersmith and Shepherd's Bush to the west, Camden and Islington in the north, Battersea and Lambeth across the Thames to the south, absorbing all of them, just as a pool of mercury encounters and incorporates smaller beads of mercury, leaving only their names behind.

London grew into something huge and contradictory. It was a good place, and a fine city, but there is a price to be paid for all good places, and a price that all good places have to pay.

After a while, Richard found himself taking London for granted; in time, he began to pride himself on having visited none of the sights of London (except for the Tower of London, when his Aunt Maude came down to the city for a weekend, and Richard found himself her reluctant escort).

But Jessica changed all that. Richard found himself, on otherwise sensible weekends, accompanying her to places like the National Gallery and the Tate Gallery, where he learned that walking around museums too long hurts your feet, that the great art treasures of the world all blur into each other after a while, and that it is almost beyond the human capacity for belief to accept how much museum cafeterias will brazenly charge for a slice of cake and a cup of tea.

"Here's your tea and your éclair," he told her. "It would have cost less to buy one of those Tintorettos."

"Don't exaggerate," said Jessica cheerfully. "Anyway, there aren't any Tintorettos at the Tate."

"I should have had that cherry cake," said Richard. "Then they would have been able to afford another Van Gogh."

Richard had met Jessica in France, on a weekend trip to Paris two years earlier; had in fact discovered her in the Louvre, trying to find the group of his office friends who had organized the trip. Staring up at an immense sculpture, he had stepped backwards into Jessica, who was admiring an extremely large and historically important diamond. He tried to apologize to her in French, which he did not speak, gave up, and began to apologize in English, then tried to apologize in French for having to apologize in English, until he noticed that Jessica was about as English as it was possible for any one person to be. By this time she decided he should buy her an expensive French sandwich and some overpriced carbonated apple juice, by way of apology, and, well, that was the start of it all, really. He had never been able to convince Jessica that he wasn't the kind of person who went to art galleries after that.