He didn’t have the energy to defy her, no matter how much fun it might have been. And he wanted his bag back without it being stamped on. He sat through the rest of the liturgy, hearing the words in plain English, but not understanding the symbols. People stood, sat and knelt at intervals, then trooped to the altar rail to receive a piece of translucent wafer.

Then the service was over, and it was him, the priest and Sister Madeleine.

“So soon, Petrovitch?” said the nun. She turned and heaved the doors shut. “Strange the things you find important.”

“Yeah,” he said. The priest had disrobed, and was walking slowly down the center aisle in his black cassock and Roman collar. “It’s not like I came to see you.”

“That would never happen,” she said, banging the bolts into place. The sound reverberated around the nave. “This is Father John, priest in charge.”

“Father,” said Petrovitch, and raised his hand briefly. The man who came over and shook it with wary firmness couldn’t have been much older than he was.

“What do I call you?” said the father, scraping his fingers through his heavy fringe.

“Petrovitch will do. Is it me, or is the world being run by a bunch of kids?”

“Father O’Donnell was murdered two months ago. The parish needed someone.” Father John sat in the pew in front and twisted round to face Petrovitch. “I go where I’m sent.”

“Very noble, I’m sure.”

“But bringing extra trouble to our doorstep when we’ve more than enough of our own, that’s not. The sanctuary’s violated yet again, mass is delayed, and the police are here, throwing their weight around.”

“When Father O’Donnell died, they didn’t want to know,” said Sister Madeleine. “No investigation, no forensics, no arrests, no one to face justice. We know who did it, but no one’s interested.”

“I’m sorry about that,” said Petrovitch.

“I’m here to make sure they don’t need to let us down again,” she said. Her face hardened and she stared into the distance.

The priest picked underneath his nails. “A good man dies, and nothing. You and that girl turn up, and we have everything we didn’t have before. And who for? Two dead criminals.”

“If it was a detective inspector called Chain, don’t take it personally: he’s got a grudge against the Oshicoras.”

Father John scratched at his ear, where there was a notch missing from the cartilage. “Sister Madeleine shouldn’t have left the church, either. I’ve told her novice master. Penance will have to be done.”

Petrovitch glanced at the man and raised his eyebrows. “She’s in trouble? Because of me?” He started to smile.

Father John tried to wipe the smirk off Petrovitch’s face with sheer force of will, but Petrovitch was having none of it. “Yes. She’s here to protect her church and her priest. Not passing strangers. A member of the Order of Saint Joan has legal exemptions while she’s doing her duty, none when she goes off and does her own thing.”

“She didn’t shoot anyone.”

“She could have done a life sentence if she had.” Father John’s voice rose in volume until he was yelling, bare centimeters from Petrovitch. “She’s not the police. She’s not even a paycop. I don’t thank you for putting her vocation in jeopardy before it’s barely begun.”

“Yeah. Okay. I get the message, Father. Just get me my bag; sooner I get what I want, the sooner you can get me out of here.” Petrovitch made sure his smile grew wider and he snorted. “You take yourself far too seriously.”

The father got up and cast him a baleful look. “Don’t bring bad people here.”

“Since I’ve been called a bad man once already this morning, I’ll have to count myself among their number.”

Father John stalked off to the vestry to collect Petrovitch’s bag. Sister Madeleine leaned down and waited until the father was out of sight. “Come with me,” she whispered.

“I’m just going to get you into more trouble, and none of it the interesting kind.”

“I can look after myself. Just come.” She walked to a side door, turned the heavy key and pulled the bolts aside. Stale air blew in as she worked the latch. Petrovitch dragged himself out of the pew and followed.

There were stairs, going up in a tight spiral, which she had difficulty negotiating because of the width of each step and the height of the ceiling, and he had problems with because he grew rapidly breathless as he ascended.

She opened another door, a trap door which she unbolted and threw back. Light poured in, making them both blink. She led the way onto the roof of the tower, and turned a full circle, taking in the view.

It wasn’t much. Immediately to the north was a raised section of dual carriageway, crammed with traffic. South and east were the cramped streets of old London, the skyline filled with the skeletons of cranes and new buildings, each trying to outdo the last for height. To the west was the rising ground of Notting Hill, where the wealthier post-Armageddon refugees had squatted.

Petrovitch leaned heavily on the parapet and wiped his damp forehead with the back of his hand. “I can’t believe you’ve got me all the way up here just for this.”

“Look,” she said, pointing beyond the flyover. “See those buildings? That’s the Paradise housing complex. It used to be St. John’s Wood, before they bulldozed half of it.”

“Yeah,” said Petrovitch. There were seven tower blocks, ugly, utilitarian shapes, their bases hidden in a yellow haze. The concrete looked scarred and cracked. “Doesn’t look like they deserve the new name.”

“They call themselves the Paradise militia,” she said, and leaned on an adjacent piece of brickwork, staring out over the city with faraway eyes. “They run the blocks, and everybody in them. It’s like a city-within-a-city, with an economy based on crime. That’s who Father O’Donnell took on.”

“So they killed him. Shame, but I don’t know why you’re telling me this.”

“I want you to understand.” She tilted her head to face him, brushing the side of her veil away where it obscured her view of him. “Father John…”

“I understand too well. He’s just a boy. Like me.” Petrovitch laughed, and it hurt in a way that reminded him that he was still alive and how much he had to lose. “Father John thinks he can take the place of the martyred O’Donnell and win the souls of Paradise. He’s deluded by dreams of glory and can’t see that he’s going to go the same way.”

“They hate us. They act like we’re another gang, moving in on their territory. You’re right: they’d kill Father John, too, if they could. But he has me,” she said.

“So what’s your life expectancy measured in? Weeks or days?” He looked her in the eye, briefly, before feeling the need to count the lace holes in his boots.

She gathered her blowing veil and held it over her shoulder. “Someone has to do something.”

“I bet that’s what the Armageddonists said, right before they…”

He didn’t finish his sentence. His feet left the ground and, for a moment, he thought he was going over the parapet.

“Don’t,” she screamed in his face. Her fists were balled up in his collar. “Don’t ever. This is their fault. Everything. I could have been little Madeleine instead of this. I could have been normal.”

Then the calm after the storm. She lowered him rather than just letting go. His toes gratefully found the concrete roof.

“I’m not like them,” she said. She straightened his jacket out, sweeping her long fingers over the folds in the cloth. His skin burned under her touch. “I could never be like them.”

Petrovitch dared to move, retreating until his back was against the brickwork. When it eventually came, his voice was high and panicked. “I’m going now. For both our sakes.”

She waited until he was ducking down out of sight before calling after him. “Do you believe me?” she asked.

“What? That you feel the need to die in a futile gesture? Yeah. Russians have been throwing their lives away for nothing for centuries: it’s in the blood.” He started down the steep steps. “I don’t intend to join them.”