It was still early—­not quite ten o’clock—­and it occurred to Aubrey that if he was going to patrol the neighbourhood he had better fix its details in his head.  Hazlitt, the next street below the bookshop, proved to be a quiet little byway, cheerfully lit with modest dwellings.  A few paces down Hazlitt Street a narrow cobbled alley ran through to Wordsworth Avenue, passing between the back yards of Gissing Street and Whittier Street.  The alley was totally dark, but by counting off the correct number of houses Aubrey identified the rear entrance of the bookshop.  He tried the yard gate cautiously, and found it unlocked.  Glancing in he could see a light in the kitchen window and assumed that the cocoa was being brewed.  Then a window glowed upstairs, and he was thrilled to see Titania shining in the lamplight.  She moved to the window and pulled down the blind.  For a moment he saw her head and shoulders silhouetted against the curtain; then the light went out.

Aubrey stood briefly in sentimental thought.  If he only had a couple of blankets, he mused, he could camp out here in Roger’s back yard all night.  Surely no harm could come to the girl while he kept watch beneath her casement!  The idea was just fantastic enough to appeal to him.  Then, as he stood in the open gateway, he heard distant footfalls coming down the alley, and a grumble of voices.  Perhaps two policemen on their rounds, he thought:  it would be awkward to be surprised skulking about back doors at this time of night.  He slipped inside the gate and closed it gently behind him, taking the precaution to slip the bolt.

The footsteps came nearer, stumbling down the uneven cobbles in the darkness.  He stood still against the back fence.  To his amazement the men halted outside Mifflin’s gate, and he heard the latch quietly lifted.

“It’s no use,” said a voice—­“the gate is locked.  We must find some other way, my friend.”

Aubrey tingled to hear the rolling, throaty “r” in the last word.  There was no mistaking—­this was the voice of his “friend and well-wisher” over the telephone.

The other said something in German in a hoarse whisper.  Having studied that language in college, Aubrey caught only two words—­ Thur and Schlussel, which he knew meant door and key.

“Very well,” said the first voice.  “That will be all right, but we must act to-night.  The damned thing must be finished to-morrow.  Your idiotic stupidity—­”

Again followed some gargling in German, in a rapid undertone too fluent for Aubrey’s grasp.  The latch of the alley gate clicked once more, and his hand was on his revolver; but in a moment the two had passed on down the alley.