It hit again, and something in the lock sheared.

On the third impact the great insulated door burst inward, and a rush of merely-cold ordinary air flooded in, and it felt, against that arctic vault, as warm as summer.

Marcus sprinted in — and stopped dead, because I was not standing.

I was on the cardboard on the floor, and I was holding, against my chest, a tiny, furious, crying newborn.

“There’s another one,” I gasped through lips I could no longer feel.