‘What?’ I asked. ‘Where did he go?’

Winter folded his arms across his broad chest and glowered. ‘He’s vanished. He cast a spell to stop himself from being tracked like this. That means only one thing: the thief is definitely from the Order.’ There was a harsh note in his voice, as if he were personally hurt that a fellow Order witch would stoop to such an act.

‘So that’s it?’ I cocked my head, disbelievingly. ‘We’ve waited for two hours to get a bunch of herbs together which told us nothing more than that there’s one of them and he’s a male witch.’ I threw my hands up in the air. ‘What a waste of time. Can’t your herbs counter their runes?’

‘Obviously not,’ Winter said grimly. ‘And just because we can only see one doesn’t mean there is only one.’

‘There must be some other way of—’

‘Ms Wilde! Enough of this.’

I sighed. He really was very upset. ‘Okay, okay.’ I paused. The thought that Eve’s two intruders had cast this very same spell to see what she’d been up to in her flat was creepy as hell. It was like the witchy version of a secret camera. ‘What happens if you use the same herbs but with different amounts?’ I enquired.

‘It’s not going to change anything,’ Winter replied stiffly. ‘We won’t see any more than we just have.’

‘Humour me.’

Maidmont answered for him. ‘If you add more aconite and use it as the last ingredient, you can see future actions.’

I blinked. ‘You can tell the future?’

‘Even in its strongest form and applied by the most talented witch, it only shows you the next twelve minutes and it’s hopelessly unreliable,’ Winter said. ‘If you saw yourself doing a jig in about six minutes’ time, all you have to do is not do the jig and then you won’t be jigging.’

His explanation was convoluted but I thought I understood. ‘The future’s not immutable, you mean.’

‘Exactly.’

I pondered this. ‘And are there any other applications? Any other uses?’

Again, it was Maidmont who answered. ‘If you increase the number of bakuli pods then the herbs can be used to track people.’

‘Track?’

Maidmont’s expression was animated. He seemed to really enjoy playing the role of knowledge-giver. No wonder he was a librarian. ‘If you can get close enough to someone to sprinkle some of the concoction onto them, you can use the remainder to follow where they go. It’s similar to the breadcrumb theory but far more advanced. Naturally.’

‘Naturally.’

Winter snorted. ‘It’s a stupid application. Any witch beyond Second Level can easily create long-term guards against such spells.’

‘But, Adeptus Exemptus Winter,’ I pointed out, ‘not everyone is a witch.’

‘If anyone is worried about being followed in this manner, all they need to do is pay the Order to ensure they are warded against such a spell.’

Assuming they knew it existed in the first place. Seeming to read my thoughts, Winter jumped in before I could argue my point. ‘How do you know all this?’ he asked Maidmont. ‘This is higher Level magic.’