The back door of Sanstead House opened on to a narrow yard, paved with flagstones and shut in on all sides but one by walls. To the left was the outhouse where the coal was stored, a squat barnlike building: to the right a wall that appeared to have been erected by the architect in an outburst of pure whimsicality. It just stood there. It served no purpose that I had ever been able to discover, except to act as a cats' club-house.

Tonight, however, I was thankful for this wall. It formed an important piece of cover. By keeping in its shelter it was possible to work round the angle of the coal-shed, enter the stable-yard, and, by making a detour across the football field, avoid the drive altogether. And it was the drive, in my opinion, that might be looked on as the danger zone.

The Nugget's complaints, which I had momentarily succeeded in checking, burst out afresh as the rain swept in at the open door and lashed our faces. Certainly it was not an ideal night for a ramble. The wind was blowing through the opening at the end of the yard with a compressed violence due to the confined space. There was a suggestion in our position of the Cave of the Winds under Niagara Falls, the verisimilitude of which was increased by the stream of water that poured down from the gutter above our heads. The Nugget found it unpleasant, and said so shrilly.

I pushed him out into the storm, still protesting, and we began to creep across the yard. Half-way to the first point of importance of our journey, the corner of the coal-shed, I halted the expedition. There was a sudden lull in the wind, and I took advantage of it to listen.

From somewhere beyond the wall, apparently near the house, sounded the muffled note of the automobile. The siege-party had returned.

There was no time to be lost. Apparently the possibility of a sortie had not yet occurred to Sam, or he would hardly have left the back door unguarded; but a general of his astuteness was certain to remedy the mistake soon, and our freedom of action might be a thing of moments. It behoved us to reach the stable-yard as quickly as possible. Once there, we should be practically through the enemy's lines.

Administering a kick to the Nugget, who showed a disposition to linger and talk about the weather, I moved on, and we reached the corner of the coal-shed in safety.

We had now arrived at the really perilous stage in our journey. Having built his wall to a point level with the end of the coal-shed, the architect had apparently wearied of the thing and given it up; for it ceased abruptly, leaving us with a matter of half a dozen yards of open ground to cross, with nothing to screen us from the watchers on the drive. The flagstones, moreover, stopped at this point. On the open space was loose gravel. Even if the darkness allowed us to make the crossing unseen, there was the risk that we might be heard.

It was a moment for a flash of inspiration, and I was waiting for one, when that happened which took the problem out of my hands. From the interior of the shed on our left there came a sudden scrabbling of feet over loose coal, and through the square opening in the wall, designed for the peaceful purpose of taking in sacks, climbed two men. A pistol cracked. From the drive came an answering shout. We had been ambushed.

I had misjudged Sam. He had not overlooked the possibility of a sortie.