“WHAAA—?” she said, starting awake in a panic, then realizing through her foggy brain that if it was a murderous rapist, he was very much going about it in completely the wrong way. She had been on the train again, the tiny dusty train, with the woman in her hat, the tunnel coming closer, closer . . .

She glanced at the toes wriggling frantically two centimeters from her nose. “Phoebe? Is that you?”

Under the blankets came a tiny eep.

“What on earth is the matter?”

The little body was shaking.

“At least turn the right way up.”

There it was then: a boom, and the little body went rigid. Carmen leaned out and switched on her bedside lamp, which did almost nothing except make the rest of the dark room even darker. There was something odd about the light, something soft about the noise, but the boom . . .

“What was that?”

Slowly, gradually, like trying to tempt an animal out of its burrow, Carmen stroked Phoebe’s back and gradually persuaded the child to turn the right way up.

“You’ll suffocate down there,” she said, as Phoebe’s stubborn black eyes and shock of messy hair finally emerged over the top of the duvet. Phoebe didn’t smile. She was whispering.

“It’s the . . . thundersnow!” she imparted.

“Oh, of course it is!” said Carmen. “Amazing!” She frowned. “I thought you’d have gone to Skylar.”

Phoebe shook her head.

“Skylar says sleep heen is very important.”

“‘Sleep heen’?”

“Yes. Never disturb someone’s sleep. It is very important. To be clean.”

“Sleep hygiene?” said Carmen, waking up slowly.

“Oh yes. Anyway. It’s scary.”

“Oh no, I’m sure it’s not,” said Carmen, swinging out of bed and wincing. She wished she knew why Sofia thought keeping your bedrooms warm was common. The polished wood beneath her feet was like ice.

“Don’t go!”

“Come on, I’ll just take a look . . .”

Phoebe pushed herself back under the duvet, hunched over with her head over her knees. Carmen vowed that she was going to overcome her lifelong hatred of slippers—she had an unnatural aversion to sheepskin—otherwise she was going to get chilblains.

You couldn’t see anything from down here in the basement, but the world outside was in a deadly hush, the window absolutely freezing to the touch, and Carmen felt a rush of excitement.

“Come on,” she said. It was just before 5:00 A.M. Phoebe shook her head severely. “Just . . . come and have a look. A quick one. How about we bring the duvet with us?”

Phoebe looked worried, so, in the end, Carmen half picked up the trembling girl along with the duvet and took them both up the stairs to the kitchen, which still had vestigial warmth from dinner, and the back window that looked over the little garden.