Winter sighed. ‘Why?’

‘First of all,’ I said, ticking off my fingers, ‘he’s eating lunch at his desk. He doesn’t have enough time to take a break because he’s spending all his free time reading Volume 9. Secondly, he knew Diall well enough to get all the gossip about him, so he definitely knew him well enough to be invited into his home where he murdered him. Thirdly, his tie has yellow stripes. Never trust someone wearing yellow.’

‘What’s wrong with yellow? It’s the colour of sunshine.’

‘It makes me look sallow and washed-out.’ Winter took a deep breath and I grinned. ‘Are you counting to ten?’

‘Your theories are quite extraordinary, Ivy. Besides, I thought you were convinced that Price did it.’

‘I changed my mind. It’s a lady’s prerogative.’

Winter halted abruptly. Slowly, he turned towards me. ‘You … you’re a lady?’

Ha. Ha. Ha.

***

Trumpton Avenue sounded considerably more upmarket than it actually was. Instead of a leafy road with pretty Victorian houses, which is what I’d imagined, Winter and I found ourselves in Oxford’s version of hell. Although I’m sure that the council serves this area in the same way as the rest of the city, the road was strewn with rubbish ranging from old beer cans to cigarette ends.

On one side of the street, a shabby man mumbled to himself as he shuffled along. When he saw us he yelled a warning about two-headed sheep then shook himself and continued on his way. A scrawny cat, thankfully ginger rather than black, crossed our path and gave a defiant hiss in Winter’s direction. The houses were small, often with boarded-up windows. They were also covered in a layer of grime which archaeologists would probably find fascinating.

‘I bet they don’t put this place in the tourist brochures,’ I said.

Winter didn’t answer though he appeared horrified. It didn’t help when we discovered that number two wasn’t before house numbers four and six, as you might expect. No, that would have been too easy. Instead, it was wedged in a terrace further down, as if the town planner had been having some fun and decided to rewrite the laws of basic arithmetic.

Winter gently nudged me out of the way so that he was the only person on the doorstep when he rang the bell. I picked some dirt out of my fingernails. If he was so keen to do all the work, let him get on with it. My mouth was parched and my sock was still wet. At this rate, I wouldn’t have to feign illness; I’d end up in hospital with pneumonia. Or some kind of terrible bacterial infection.

Winter wasn’t in the mood for waiting. When no one answered the doorbell, he knocked loudly. When that didn’t work, he shouted, ‘Oscar Marsh! This is Arcane Branch! Open up!’ He knocked some more, the force of his fist making the flimsy door rattle and shake in its frame.

‘You could try turning the doorknob,’ I suggested. ‘It would take a lot less effort.’

Winter wasn’t ready to take the easy route. He knocked some more, with increased vigour. Without a warrant, he probably couldn’t enter a property unless he had the owner’s permission. I could fix that. I didn’t want to stand here all day.

Taking a step backwards, I focused on the rusty doorknob. Like the rest of the house, and indeed this street, it had seen better days. It didn’t matter what it looked like; the rune I’d developed was to avoid having to root around in the bottom of my bag for my keys. That might not sound like a particularly arduous task but, given the amount of crap I carry around with me, it could take some time to find what I needed. With this little magic rune, I didn’t have to worry about losing my house keys – and Winter and I wouldn’t have to stand out here until his knuckles were bloody.

With his back towards me, it was easy for me to sketch out the rune without him noticing. I added a little pinkie flick at the end as a flourish, which had precisely the desired effect. The doorknob turned and the door creaked open. Not by much but enough to reveal the dank and musty corridor beyond.

‘Hey,’ I said cheerfully. ‘He must have heard you. Let’s go.’ Before Winter could argue, I nipped past him and went in, although the reek inside almost made me wish I hadn’t.

Irritated, Winter stepped over the threshold and joined me. He looked at me suspiciously, as if he were sure that I’d had something to do with the door’s miraculous opening. The whiff that reached his nose and made it wrinkle gave me the chance to forestall any pointed questions. ‘Smelly, huh?’ I said.

Winter shook his head. ‘I’ve never smelt anything like it before.’

I stared at him; he had to be kidding. ‘Chips and curry sauce,’ I said. I lifted my nose and sniffed. ‘And, if I’m not mistaken, just the faintest tinge of three-day-old doner kebab.’

Now it was Winter’s turn to look astonished. ‘People actually eat doner kebabs?’

‘What else would they do with them? You can’t beat a good kebab.’ I smacked my lips. ‘Especially with slatherings of chilli sauce.’ I grinned. ‘Let me guess: you’re a vegetarian?’

‘No, I’m not. But I don’t eat garbage like that.’

I hadn’t seen him eat anything yet; so far, he’d seemed to exist on air and a furrowed brow. My stomach gurgled to remind me that it was some time since I’d eaten anything substantial myself.

‘I made dinner last night,’ Winter said. ‘I even went shopping. You’d have noticed if you hadn’t crammed a chocolate bar into your mouth then fallen fast asleep.’

He’d cooked? Before I could ask what he’d made, there was a loud groan from a room nearby. Winter stiffened and shot me a warning glance as if I needed telling to keep quiet. I tutted softly.

We edged further in. Someone was definitely in the house; there was the sound of soft snoring. It was a wonder that they’d not woken up when Winter bellowed at the entrance. I nodded in satisfaction; that sort of dedication to sleep always impresses me.

Treading lightly, Winter walked in front of me and paused at the end of the gloomy corridor. He knocked on the door. The snoring continued. Nudging the door with his foot, he pushed it open. Inside there was a dimly lit room with large sash windows, draped with heavy velvet curtains. They would have looked rather grand but they were hanging off the rail in several places and looked as if they’d been flung up rather than carefully dressed. There was a flickering television screen in one corner and my gaze took in an extraordinary pornographic video involving several naked people and orifices I had no desire to think about. Winter hastily grabbed the remote control from the floor and switched it off.

The only other thing in the room, apart from empty bottles and squashed cans, was a sofa with a large lump on it. When the lump let out another snore, I decided that this had to be Oscar Marsh. For all that Adeptus Diall had seemed to be an unpleasant fellow prior to his untimely death, he appeared to have hit the nail on the head as far as Marsh was concerned. I doubted this was an Order witch of whom the Ipsissimus was particularly proud.

I wondered if it troubled Winter that he spent his time around less than noble witches when the Order did so much good for the world. I suppose it was the nature of his job – of our job.

Winter cleared his throat. If he thought that was going to wake Sleeping Beauty, he was deluded. Marsh was face down with his arse sticking up in the air and one arm dangling over the sofa’s edge. Considering what Winter had done to force me out of bed, I was surprised that he was being so delicate. ‘Throw a bucket of water over him,’ I said sourly. ‘It worked with me.’

Winter grimaced. ‘That was because I knew you weren’t likely to spring up and start attacking me. This guy is another matter.’

I frowned. ‘First of all, this guy is virtually comatose. Even when he wakes up, he’s hardly going to be in a position to attack. Alcohol is seeping out of his pores, Winter. He’s more likely to throw up and clutch his head than throw something at your head. And how did you know I wouldn’t attack you? I might have.’

‘You’re not the type,’ Winter dismissed, without explaining properly. ‘If this Marsh killed Adeptus Diall, not to mention stole the Cypher Manuscript, then he’s far more dangerous than he looks.’