Wedged tight like a doorstop in my mother’s arms, I concentrated on being still and quiet, and waited to feel safe again. But she wasn’t making it easy. Her body, normally so soft and comforting, was rock-hard, and every time I felt the warm whoosh of her breath in my hair, her arms tensed and she made a low, hollow noise, like she was in pain. I concentrated harder, counting one to ten, and onwards. I didn’t move a muscle. Not a finger. Not an eyelid. Not a hair.

And the more I counted, the calmer I felt, and the fainter the vibrations of my banging heart. Not a whisker. Not a blink. Not a breath.

Not. One. Breath.

I kept my eyes shut and my arms locked tight around the stranger in my mother, stiff as a board with my lips and nose sealed up like a vault. It was so lovely and quiet in there, and it felt like I was swimming through warm, silky honey. I swam and swam, and the whooshes of air through my hair slowed down, and my mother’s body got softer and more familiar. When she was finally still, I opened my eyes and gulped a huge breath of cold, new air into my lungs. We stayed in the hug for a long time, though, and my mind was racing with the thrilling, wonderful, terrifying knowledge of what I’d done.

Even though that woman continued to come and go from my mother’s bedroom more and more frequently after that day, I was never as scared as that first time, because I knew I could help. I could do magic, and the magic worked.

I only found out later that it hadn’t actually been the first time at all. I was maybe nine or ten by then, and Lou picked me up early from school on a Friday and said we were going on an adventure. We got on a train at St Pancras and headed to Rye on the coldest day of the year. When we got there, we checked into a B&B and spent the weekend going on freezing walks and eating takeaway curry in bed, and Lou was properly happy the entire time. I don’t think I truly understood the times she wasn’t happy until I had that weekend to compare them to.

When we came in from a gusty three-hour walk along the coastline, wet through, numb to the knees, mud-splattered from head to toe, we’d sat on the floor, laughing at our blue lips until copious cups of tea brought them back to the right colour. Lou dried off my hair and told me about the time my mouth had gone that same shade of blue when I was a baby. She’d been so terrified she rushed me to the hospital in a black cab, even though I was perfectly fine and it had only been for about thirty seconds. But it was the longest half a minute of her life, she said.