On the morning Mira died, something happened in the Veil that no one could explain. In the Thornwood, at the precise hour and minute that a woman named Mira drew her last breath in a house on Elm Street in Connecticut, a tree bloomed. Not in the way trees bloom in spring—with anticipation, with the gradual swelling of buds, with the patient unfurling of petals. This bloom was instantaneous. One moment the branch was bare, silver-barked and silent as all branches in the Thornwood were silent, an...