Even though I’d been sunk in the depths of a deep, deep sleep, the unmistakable pig squeal of the fourth stair had reached the part of the brain that never sleeps. I had no doubt what I’d heard, and I had no doubt what it meant: someone was in the house. The fluorescent display of the alarm clock on my bedside table said 3:33. I could feel my heart pounding in my chest like something with a life of its own, like a rabbit writhing and twisting in a snare that grew tighter the more it struggled. I strained to hear above the booming roar in my temples. My ears probed outside my bedroom door – the landing, the staircase – like invisible guard dogs, constantly sending back information: silence, silence, silence, there’s only silence: we can find nothing. Could I have been mistaken? But I knew I wasn’t. I’d heard the fourth stair scream under a person’s weight. Sure enough, after what seemed like an eternity of waiting there came the groan of another stair, a higher stair: someone was in the house.