"Boo," he said, his thick voice just as deep and dangerous as that of the man upstairs.

I staggered backward, shaking my head. The man had left only one escape route-the way we'd come in. I bolted through the sitting room door, ready to fling myself screaming from the window. But what I saw in that room drained the strength from my body, turning my legs to jelly. It took everything I had to remain upright.

The room, which had been deserted less than five minutes ago, was now full of men. Each was almost identical in size, dwarfing the furniture and making the large space feel like a doll's house-each almost identical in looks too, like brothers. And they were all wearing the same immaculate black suits. I counted four in all, and the sound of footsteps behind me made it clear that the other two were in the hall.

But the figure I couldn't take my eyes off was standing in between the giants, twitching and shaking like he was having a fit. He looked tiny in comparison, barely reaching the elbows of his comrades, and wore a long, black leather coat that made his bald head look like pale parchment.

I knew now why Toby had been screaming. The man was wearing what looked like a gas mask-an antique, rusted device that covered the lower part of his face and stretched over his shoulder to a tank on his back, like the ones worn by divers. He wheezed noisily through the ancient contraption as if he was having an asthma attack. Peering over the top of the mask, like two raisins set into rancid porridge, were his eyes, and the way they stared at me made me want to curl up and die.

It took me a few moments to notice the frail, shaking body of Toby on the floor beneath one of the men in black. He stared at me with a look of pure terror, his eyes wide, pleading for me to help him. I didn't know what to do, I didn't even know who the men were. Taking another look at the shriveled figure by the window, I found myself praying for the familiar uniforms of the police, not this freak show of gas masks and goliaths.