Snow was sifting down over the city, but Sam was sweating by the time he reached the University Church. He had stomped all the way up here, his breath steaming on the air and making him look even more like a fuming beast. Nobody had waylaid him with idle conversations.

He wasn't, in truth, that angry. He didn't know what he was. But anger was something he knew, and seemed like an emotionally safe place to be, so he shrugged on its mannerisms like a well-worn coat, and allowed it to guide him up the hill to the High Street.

It left him on the threshold of the church doors. The chill suddenly set in, curled its fingers round his jaw and turned his head, until he was looking longingly back the way he had come. He might have gone straight home if Manda hadn't spotted him.

"Are those my books? Shut the door, will you? I'm freezing."

He was carrying a small wooden crate in his arms. Its contents jangled now as he hefted it into a more comfortable position, revealing the fact that it did not just contain books. In fact, it contained enough artillery to equip a small army – which was, he supposed, exactly what it was going to do. An army of twitchy old women who cried for a living. But Manda had asked him, and he didn't seem to be able to say no to Manda these days.

Sam grunted and kicked the doors shut behind him. At least the workmen had gone home. He would probably not have the courage to say what he had come here to say, but even bumbling fruitlessly around the subject would have been made more difficult by company.

"Are they heavy?" she asked, as he came closer, lumbering through the dim candlelight. "Why didn't you take a cab here? Just look at you!"

He dropped the crate onto the nearest pew, and she passed him a handkerchief to wipe his brow. 

She was freezing. There were goose-bumps under the black, gauzy material of her dress. It was not compulsory for mourners to dress this way – in fact, she was wearing what might have been referred to as summer mourning attire. But it was like her constant working, her constant holding of that broom, the fact that she was here at all hours now, overseeing work that could have gone on perfectly well without her. She was trying to distract herself.

"Where's Madam Seacombe?" he said.

"I sent her back to Iffley Road. The rooms here aren't really habitable yet."

"But you're staying the night here?"

"Well, I don't have any time to habit," said Manda. "There's too much work to do."

Sam looked disconsolately at the floor. There was not a speck of dirt in sight.

He had spent the past few days cleaning out the station. It wasn't just the broken, out-of-date furnishings that were going, but the broken, out-of-date policemen: anyone who had been complicit in Jack's takeover, anyone who had looked the other way when things went missing from the evidence locker, or when the mayor dropped by and asked them not to arrest murderers because they happened to be his friends. 

He was stuck with the mayor himself, of course – and stuck with keeping Jack out of prison. Jack knew too much about the city's most powerful men, and they wouldn't risk making him angry. But they wouldn't risk making Sam angry either, because he had impounded all Jack's incriminating documents.

It was not perfect. There was no integrity to it. The job of manipulating the city's powerful men had just passed from Jack to Sam, that was all. But at least he knew he could be trusted with it.

In any case, Manda had asked for some of the old truncheons and revolvers. This had made Sam uneasy even after she'd explained that the mourners wanted to make their rebuilt premises more secure, so that no gargoyles or slave-dealers would ever sneak in and set fire to the place again. It made sense – he just didn't want to think of Madam Seacombe with a pistol under her pillow.

And Manda had also asked for some of the old manuals and books of bye-laws. She wanted to understand his work, she said. Sam had been so flattered by this that he hadn't been able to refuse, even though he suspected that a Manda who knew the exact letter of the law would be a very dangerous woman indeed.

So he had come to the University Church that night with a crate of books, pistols, truncheons and cartridges. And right at the bottom, so tucked away that he had to admit he was probably hoping she wouldn't find it until after he was gone, the box where he kept Lily's letters.

But Manda dived in before he could make his excuses, lifting out armfuls of ammunition that looked quite comical in her grip. It was the books she was eager to get at, but he saw her beaming, freckly expression change when her hand brushed the box. She had seen it before. She knew what it was.

She withdrew her hands from the crate – she didn't want to pick up the box, even to make a point. "Why are you giving me this?"

Sam gave a surly shrug. "They were written for you. They're addressed to you-"

"But I've told you before, I want you to have them. You're-" She waved a hand. "More literary. You can appreciate them more."

Sam was silent. He wanted to say that he thought no-one had ever appreciated Lily as much as she did. No-one had ever been a more faithful friend. And the fact that Lily had killed herself for want of his love when she'd already had Manda's showed... poor judgement on her part. He wanted to say that he'd only been able to see this for a few days. And there were other things he was only just beginning to see, though he seemed to have always known them.

But instead he played hopelessly with the handkerchief in his hands, folding and unfolding it, staring without seeing at the little, embroidered sun in its corner. "We could always share them," he said at last.

Manda frowned. "How do you mean? Divide them up?"

"No, I mean-" He waved the hand holding the handkerchief, as if he was surrendering. "Keep them in a place that's home to us both."

Manda continued to frown at him, so he went on, trying to make it sound as though this was an idle thought that had only just occurred to him. "If we got married, you could come to live with me in Speedwell Street, and we could keep the letters there. And share them."

Manda stared at him uncomprehendingly for a few seconds. Then she did the very worst thing possible, from Sam's perspective. She burst into tears.

He passed her the handkerchief, looking determinedly at his feet. He didn't know what to do. He put a hand on her shoulder, realizing as he did so that it looked shovel-sized against her trembling frame. God, she was so tiny, compared to him. He had never thought about the practicalities of this before. He had never thought about how far he would have to lean down to kiss her – or the fact that, if they ever shared a bed, he could easily roll over and crush her in the night.

He had only ever had one lover in his life, and he had more or less killed her. And this was his best friend – the only person who could endure his mood-swings, who had no patience with his despair, who had always been there, even though he'd taken everything from her. It was difficult to avoid feeling – what? Apprehensive? Protective? Nervous? Was it worth the risk, bringing her closer? But he had no choice. He was miserable without her these days, and she would work herself to death in this place if he let her.

He had never considered that she might say no.

It was a long time before he realized that she wasn't really crying over him – or, if she was, then he was the instigator, not the cause. She sobbed into the handkerchief, drowning that embroidered sun, for so long that he began to be afraid she couldn't breathe. But when she emerged, red-faced and wet and barely coherent, she was talking about Lily.

"She was the sun in the sky for me," said Manda, between quick, shallow, shaking breaths. "We were closer than sisters. She was always more clever-"

"Cleverer," said Sam, who knew he was saying the worst thing possible, but couldn't stop himself. Fortunately, Manda didn't seem to be listening. She choked out the words, "I thought I'd never love anyone else!"

And suddenly he was calm. Suddenly he understood. "Yes," he said, mustering smile from somewhere. "I thought so too."

She focused on him for the first time since his proposal, as though she realized that last sentence had contained a kind of admission.

"You're a bastard for not asking me sooner," she said, with a grudging, sniffly smile.

Sam conceded that he probably was. He didn't know how to tell her that it had been like emerging from a fog. For ten years, there had been no horizons – just the job in front of him – and now the air was finally beginning to clear. Now he could see wobbly shapes through the haze. And the first, loveliest outline he had seen had been hers. He'd had an overpowering urge to follow her around until he got his bearings.

And yet it hadn't seemed like a fog, at the time. When he'd been living those ten years, they had seemed like pinpoint clarity. He remembered coming down with a fever in the year he'd matriculated, and lying on his bed for days that had seemed like weeks, thinking he had solved the secrets of the universe. He had been convinced he could see the motions of the stars through his bedroom-ceiling – an impractical delusion, because he hadn't even been on the top floor. He would have seen a lot of similar, drab, untidy student bedrooms if he'd really been able to see through walls.

Later, they had told him how close to death he'd been, and he remembered thinking that it had been the kind of death-bed clarity you read about in novels, where everything had meaning and seemed to take an ice-age to occur, and you could see your whole life play out in the space of a few seconds.

The past ten years – everything after Lily's suicide – had been exactly like that fever. His mind had raced, he'd been absorbed, he had solved crimes quite brilliantly, although he had let Jack and Miss Syal run rings around him, in their different ways. But it hadn't been real. It hadn't been life. He hadn't been able to look around him. He had seen events of cosmic significance but looked right through the student bedrooms.

Was that what grief was like, he wondered? Like being in the extremity of death all the time? And you could think faster and clearer than you'd ever thought before, but the only thing you could think about was the fact that you were going to die?

There was more uncertainty now, and that was how he knew it was closer to the truth. Any state of mind which made you think you had all the answers ought to be mistrusted as a matter of course.

He looked back at Manda, who was unceremoniously blowing her nose. She hadn't wasted years in a fog of feverish clarity. She had settled down to a life of helping people – put her grief to good use. She had even helped him, although she'd had by far the greater reason to feel sorry for herself. Years ago, he would have dismissed this resilience as stupidity, but he knew better now – or he thought he did.

"How did you do it, Manda?" he asked, while she tried to tidy herself up. "How did you just get on with things like you did?"

Manda's forehead wrinkled. "What? I don't know. I'm just a different person."

"I've always liked that about you," said Sam. A smile was trying to break through his frustration, and he didn't struggle against it for long.

That was the answer to envy, he supposed. Other people were different people. It wasn't that they'd had the chance you'd never had. They'd had a hundred million different chances to your hundred million chances – some of them taken, some of them missed – and a dizzying combination of them had resulted in what you might term their success, although even that probably didn't look the same through their eyes. Comparing yourself to another person was just like the fever. It was too suspiciously simple.

"You didn't answer me," he said, when she finally looked up from her handkerchief.

"Yes I did. I said you were a bastard for not asking me sooner."

"Was that a yes?" said Sam. "Yes, I want to marry you, you're a bastard?"

"It was 'Yes, I want to marry you, even though you're a bastard'," said Manda, with a prim little sniff. "And if my acceptance wasn't very romantic, you should consider that neither was your proposal."

Sam put his hand back on her shoulder, not knowing what to do next. How did you kiss someone you knew as well as Manda? She would know exactly what you were trying to do, and exactly how far you'd fallen short of your expectations.

But because she knew exactly what he was trying to do, she kissed him first, standing on tiptoe, hands placed firmly on her hips, as though she was proving a point. He didn't argue.

Later, he would learn that, at this exact moment, Jack had been in bed with Miss Syal, achieving a much more dramatic connection. And he would think, 'How typical of Jack, always trying to go one better'. But he wouldn't mind that much, because he didn't think Jack had gone one better, in the end. His little Manda, kissing him petulantly – as though he had told her a thousand times not to do it, and she didn't care for his advice at all – was a situation that couldn't be improved upon.