On a certain night in mid-January, exactly ten years after Andrew Henderson's death, any one of the multitudinous inhabitants of London whom business or pleasure carried to that division of Brompton known as Hellier Crescent, would undoubtedly have been attracted to the house distinguished from its fellows as No.

8.
Outwardly, this house was not remarkable.

It possessed the massive portico and the imposing frontage that lend to Hellier Crescent its air of dignified repose; but there its similarity to the surrounding dwellings ended.

The basement sent forth no glow of warmth and comfort, as did the neighboring basements; the ground-floor windows permitted no ray of mellow light to slip through the chinks of shutter or curtain.
From attic to cellar, the house seemed in darkness, the only suggestion of occupation coming from the occasional drawing back and forth of a small slide that guarded a monastic-looking grating set in the hall door.
And yet towards this unlighted and unfriendly dwelling a thin stream of people--all on foot and all evidently agitated--made their way continuously on that January night between the hours of ten and eleven.
The behavior of these people, who differed widely in outward characteristics, was marked by a peculiar fundamental similarity.

They all entered the quiet precincts of the Crescent with the same air of subdued excitement; each moved softly and silently towards the darkened house, and, mounting the steps, knocked once upon the heavy door.