The noise was incredible: all the sounds of an indoor thunderstorm, edged with an unnatural high-pitched whine, like nails being dragged across a chalkboard. With her free hand she grabbed hold of an oak bookcase, her grip so tight that the wood groaned under her touch.

A standing floor lamp tilted precariously, fell with a crash and was dragged across the floor until it picked up speed and lifted off completely. For a moment the cord drew taut and the lamp remained suspended in the air, tethered like a kite, until it detached from the wall socket with a snap and disappeared inside the cloud.

Wide-eyed, Cat watched it all happen. Whatever the thing was, once it got hold of something there was no retrieving it.