He began to hunt about among the debris which littered one end of the cellar, testing fragment after fragment, but failing to find any piece of scrap to suit his purpose.  By sheer perseverance rather than by any process of reasoning, he finally hit upon the piece of bent wire which was the key to this door of Sin Sin Wa’s drug warehouse.

One short exclamation of triumph he muttered at the moment that his glance rested upon it, and five seconds later he had the trapdoor open and was peering down into the narrow pit in which wooden steps rested.  The spaniel began to bark wildly, whereupon Kerry grasped him, tucked him under his arm, and ran up to the room above, where he deposited the furiously wriggling animal.  He stepped quickly back again and closed the upper door.  By this act he plunged the cellar into complete darkness, and accordingly he took out from the pocket of his rain-drenched overall the electric torch which he always carried.  Directing its ray downwards into the cellar, he perceived Ah Fung move and toss his hand above his head.  He also detected a faint rattling sound.

“Ah!” said Kerry.

He descended, and stooping over the unconscious man extracted from the pocket of his baggy blue trousers four keys upon a ring.  At these Kerry stared eagerly.  Two of them belonged to yale locks; the third was a simple English barrel-key, which probably fitted a padlock; but the fourth was large and complicated.

“Looks like the key of a jail,” he said aloud.

He spoke with unconscious prescience.  This was the key of the door of the vault.  Removing his overall, Kerry laid it with his cane upon the scrap-heap, then he climbed down the ladder and found himself in the mouth of that low timbered tunnel, like a trenchwork, which owed its existence to the cunning craftsmanship of Sin Sin Wa.  Stooping uncomfortably, he made his way along the passage until the massive door confronted him.  He was in no doubt as to which key to employ; his mental condition was such that he was indifferent to the dangers which probably lay before him.

The well-oiled lock operated smoothly.  Kerry pushed the door open and stepped briskly into the vault.

His movements, from the moment that he had opened the trap, had been swift and as nearly noiseless as the difficulties of the task had permitted.  Nevertheless, they had not been so silent as to escape the attention of the preternaturally acute Sin Sin Wa.  Kerry found the place occupied only by the aged Sam Tuk.  A bright fire burned in the stove, and a ship’s lantern stood upon the counter.  Dense chemical fumes rendered the air difficult to breathe; but the shelves, once laden with the largest illicit collection of drugs in London, were bare.

Kerry’s fierce eyes moved right and left; his jaws worked automatically.  Sam Tuk sat motionless, his hands concealed in his sleeves, bending decrepitly forward in his chair.  Then: