Lily was exactly where she had told me she would be — sitting on the kitchen floor, her back against the lower cabinets, her small legs stretched out in front of her.

Leo was strapped to her chest in a heavy front carrier, the kind meant to be worn by an adult, squirming and crying.

And my daughter’s arms, wrapped around her baby brother to keep him supported, were trembling — not shaking with fear, but trembling with the deep, involuntary, muscular exhaustion of a body that has held a heavy weight far, far past the point where it should have been allowed to stop.

She looked up at me with tears dried on her cheeks, and the first thing my nine-year-old daughter did, the very first thing, was try to apologize.