‘Come up at once,’ Hugo whispered.  ‘Door opposite top of stairs.’

And he threw down on to the pavement a latchkey.

‘What do you think of yourself now, Si?’ Albert asked his brother, as they entered the house.  ‘You’ve let yourself in for something at last.’

They found Hugo in an ordinary bedsitting-room.  He was wearing his hat and his overcoat, and staring out of the open window.  It was a cold night, but he did not seem to feel the icy draught which blew into the apartment.  The whole of his attention appeared to be concentrated on No. 23.  He did not at first even turn to look at the brothers when they came in.  They explained themselves.

‘I will tell you why I am here, and what has occurred to me,’ said Hugo, playing, perhaps rather nervously, with the knife and cheese-plate which still lay on the small table by the window.  ’Then we can decide what to do.  I’ve hired this room.’

No doubt existed in his mind that Simon had happened upon the track of the veritable living Ravengar.  It could not be a coincidence that a man so strongly resembling Ravengar, a man posing as a doctor, and buying nearly a sovereign’s worth of chloroform, should be occupying rooms in the same house as Camilla.  The tremendous revelation of Ravengar’s genius for stratagem and intrigue afforded by the recital of the two brothers came upon Hugo with a dazing shock.  This man, whom he knew from Camilla’s own story to be curiously deficient in ordinary human sentiments, had arranged a sham suicide for the benefit of the general public.  He had let Hugo into the secret of that deception, but only to cheat him with another deception, and a more monstrous one.  The brain that could conceive the fiction of suicide in the vault—­a fiction which, while lulling Hugo into a false security as regards Camilla’s safety, at the same time poisoned his happiness—­such a brain might be capable of unimagined horrors.  Sane or mad, the mere existence of that brain was a menace before which Hugo trembled.  He realized that Ravengar had been consummately acting during the latter part of their interview on the first day of the sale, and again consummately acting when he spoke to Hugo on the telephone.  Ravengar had, beyond doubt, deliberately set himself to lure Camilla back to England, and he had succeeded.  Beyond doubt, all her movements had been spied and marked, and Ravengar had been in a position to complete his arrangements—­whatever his arrangements were—­at leisure and with absolute freedom.  She had taken a room in Horseferry Road, and he had followed....  What was the sequel to be?

That she was in his power at that moment Hugo could not question.

And the chloroform?

At that moment Ravengar had meant that the Hugo building should have been a funeral pyre—­a spectacle to petrify the Metropolis.  And it seemed to Hugo that if Ravengar was mad, as he must be, he could only have designed the spectacle as something final, as at once a last revenge and an accompaniment to the supreme sacrifice of Camilla.