‘Come,’ he said feverishly, ‘show me how you managed to get to my dome.’

And he threw open the easternmost window, and she stepped with him out on to the balcony.

They looked down across Hugo’s little private garden, into the blackness of the court of fountains, whose balconies were vaguely disclosed here and there by the reflection from lit interiors.  On the other side of the deep pit of the court was the vast expanse of flat roof containing the famous roof garden.  Amid dwarf trees and festoons of coloured lights, the figures of men and women who counted themselves the cream of London could dimly be seen walking about or sitting at tables; and the wild strain of the Tsigane musicians, as they swayed to and fro in their red coats on the bandstand, floated towards the dome through the heavy summer air.  In the near distance the fantastic shapes of chimney-cowls raised themselves against the starry but moonless sky, and miles away the grandiose contours of a dome far greater than Hugo’s—­the dome of St. Paul’s—­finished the prospect in solemn majesty.  It was a scene well calculated to intensify a man’s emotions, especially when a man stands to view it, as Hugo stood, on a lofty balcony, with a beautiful and loved woman by his side.

She was indicating pathways, as well as she could, when they both saw a man hurrying in the direction of the dome along by the roof-balustrade of the court of fountains—­the route by which Camilla herself had come.  He arrived under the dome, and would have disappeared into a doorway had not Hugo called: 

‘Shawn, I’m here!’

‘I was just coming to see you, sir,’ replied Albert Shawn in a loud whisper, as he climbed breathless up to the little raised garden beneath the dome.

Camilla withdrew behind a curtain of the window.

‘Well?’ Hugo queried.

’She’s gone, sir.  But dashed if I know where, unless she’s got herself lost somewhere on the roof.’

‘She is here,’ said Hugo, lowering his voice.  ’And it appears that you waited very clumsily at that dinner, my boy.  A bad disguise is worse than none.  I must lend you Gaboriau’s “Crime of Orcival” to read; that will teach you.  Anything else to tell me?’

‘I went back to the balcony entrance of the flat,’ the youthful detective replied humbly, looking up to Hugo in the window of the dome.  ’I could see through the lacework of the blind; the drawing-room was empty.  The French window was open an inch or so, and I could hear a clock ticking as clear as a bell.  Then Mr. Tudor toddled up, and I hid in the servants’ doorway.  Mr. Tudor went in by the other door, and out I popped again to my post.  I see my gentleman stamping about and calling “Camilla!  Camilla!” fit to burst.  No answer.  Then he picks up a photograph off a table and kisses it smack—­twice.’

Camilla stirred behind the curtain.

‘Then he goes into another room,’ proceeded Albert Shawn, ’and lo and behold! another man comes from round the corner of a screen—­a man much older than Mr. Tudor!  And Mr. Tudor runs in again, and these two meet—­these two do.  And they stare at each other, and Mr. Tudor says, “Hullo, Louis—­“’