Vale gestured to the many out-of-season flowers which crowded her attic greenhouse. ‘But you do make summer flowers grow in winter.’

‘That’s down to good gardening,’ Claribelle Houndston said firmly. ‘Not supernatural powers.’

‘Have you met him in person?’

She shook her head. ‘All our communication’s been through the post. I burned the letters after reading.’

Vale would expect no less from someone with her reputation. ‘The details of the contract, please.’

She pursed her lips, and he could tell she was rethinking her decision to cooperate. ‘Miss Houndston, bear in mind you are already heavily compromised. If the Professor finds out that I was here . . .’

‘I could present him with your corpse,’ she said speculatively. ‘That might go a long way towards convincing him of my good faith.’

‘You could certainly try,’ Vale said.

For a moment she weighed up her options, and then accepted defeat. ‘Very well. I was given two targets – you and a man named Kai Strongrock, a frequent visitor to your lodgings. That’s all.’

Vale frowned. ‘Nobody else?’

‘No, just the two of you. In fact, there was a clause in the contract that nobody else in your vicinity – or among your friends – was to be injured or damaged in any way.’

‘Is that sort of clause unusual?’

‘Not really. It can be relevant when an inheritance is at stake, for instance, and a precise order of deaths is necessary. But I admit I couldn’t see the point of it in this case. The Professor doesn’t have a reputation for sparing the innocent.’

‘Indeed.’ Vale kept his guard up, but inwardly he found himself confused. This made little sense. Why hadn’t this woman been ordered to murder Winters as well? More precisely, why were her orders almost specifically designed to ensure Winters remained safe and unharmed? ‘You will be abandoning the contract, I trust?’

‘Yes. It seems rather pointless, now I’ve alerted the primary target. I wasn’t seriously planning to go up against you, in any case. I’m abandoning the contract and London for the foreseeable future. To be frank, you and the Professor are welcome to kill one another.’ She glided past him, indicating the open window, steps confident as she wove between the rows of deadly flowers. ‘Now get out of here, before you end up dying in my attic and I turn you into compost.’

‘No doubt I’ll see you again at some point,’ he said affably.

For a moment, her expression was as lethal as her favourite poisons.

A couple of hours later – following two changes of clothing, an attempted mugging and some inconveniently persistent followers – Vale was sitting in a corner booth of a pub near the docks, nursing a pint of dubious beer. The fog outside lapped against the windows in a dank grey mass, as though the taproom had sunk beneath the Thames. Its ominous presence seemed to quiet conversation. So although the pub was busy, no one laughed, shouted or argued, and the customers hunched over their drinks, their voices muted to a background murmur.

The door creaked open and a man in battered sailor’s gear shouldered in, his dark hair and beard glistening with raindrops. Singh’s disguise wasn’t on Vale’s level, of course, but it was adequate – no one would recognize the Scotland Yard inspector. He glanced across the room, and Vale raised his tankard as a signal. Singh collected a beer of his own and joined him. As a practising Sikh he wouldn’t actually drink the stuff, but a man ordering a non-alcoholic beverage here would’ve been more noticeable than a policeman in full uniform.

Singh and Vale sipped their drinks – or feigned to – until any casual interest had died away. Then Vale opened a cheap newspaper to the racing pages, and the two men bent their heads over it.

‘Bad news, I’m afraid,’ Singh said quietly. ‘We’re being pressured to find the culprit behind the arson attack as fast as possible. Madame Sterrington’s being put forward as one of the possible suspects. Not the only one, of course – my superiors aren’t that obvious – but her name’s on the list.’

‘Inconvenient, though also informative. I learn as much from what you’re ordered to hush up as I do from what you’re allowed to pass on to me.’

‘And as long as they believe I am hushing it up, it keeps them trusting me,’ Singh agreed. ‘Otherwise I wouldn’t have been given a sniff at the records you wanted today.’

Vale nodded. He understood that the police force, like any large institution, had ways of ensuring that certain information was kept secret. Sometimes word came down that a matter had to be ‘solved’ – by whatever means necessary – to keep it out of the papers. That was when the powers-that-be found people like him useful.

Of course, word didn’t always come down from above. Sometimes it came from a distinctly lateral route. If he’d had more leisure, he would have investigated how pressure was being applied to Singh’s superiors. But time was of the essence here. ‘And did you get to see those records?’ he asked.

‘I had one of my runners pull them – together with a set of others to confuse the issue.’ Singh feigned a swallow of beer. ‘You were right that all the crimes in question show signs of a protection racket in operation, or blackmail. And all these cases were reported by concerned family members. The actual victims denied that any crime had occurred at all when the police came round to inquire. Denied it very vehemently, in some cases.’

Vale nodded. He would expect the Professor to be thorough when it came to controlling rumours of his activities. ‘Was there any police follow-up?’

‘Only in one case, and that only because the fellow committed suicide. Belson, the painter – the one who was implicated in the Flemish Primitives forgeries case, remember?’ Singh waited for Vale’s nod. ‘He’d already lost all his money and a fair amount more at cards, so when he blew his brains out nobody was surprised. But his lady friend had gone to the police earlier, claiming that he was being blackmailed. It made his death look suspicious. She apparently left town the day after.’

‘And I suspect that – conveniently – she hasn’t been heard from since.’

‘Not a word. So what do you have in mind?’

‘I’ve told you I believe a new spider has entered London’s web,’ Vale said, allowing himself just a touch of metaphor. ‘Previously, he’s been acting through agents and catspaws. But his empire has now extended far enough that even the police begin to perceive it.’

‘Miss Winters would tell you that such a spider can be female just as well as male,’ Singh noted, tankard raised to conceal a smile.

Vale snorted. ‘Very well. I concede the gender is unconfirmed until we have further information. However, I am certain of this mastermind’s presence – and I’m now sure that they’re linked to the recent assassination attempts.’

Singh turned his tankard in his hand, watching the sway of liquid rather than meeting Vale’s eyes. ‘We’ve known each other for a while now. May I speak without prejudice?’

‘Always,’ Vale answered. He was not the sort of man to talk of ‘friends’ but he had known Singh for years – nearly a decade, all in all – and he trusted the man absolutely.