arks and looking up at the Chief
Inspector. Otherwise there was no sound in the house, above or below.

Kerry stooped, and with his handkerchief scrupulously dusted the stone
slab. The spaniel, resentment forgotten, danced excitedly beside him and
barked continuously.

"There's some sort of hook to fit in that crack," muttered Kerry.

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 doo