The envelope jammed in Wren's mailbox wasn't hers. Same street, wrong number: 14 instead of 41, the digits swapped by some tired hand at the sorting office. It was addressed to a woman named Cordelia, in looping handwriting. Inside, a letter began, 'Darling, I know it's been too long, and I owe you the truth.' Wren stood on her steps, holding a stranger's letter, not sure what to do.

Wren decided to walk it over to number 41 herself. The right house had a blue door and a sleepy cat in the window. She knocked, holding the letter out like an apology. The door opened, and a young man blinked at her, confused. 'I'm looking for Cordelia,' Wren said.

The man took the letter and frowned. 'There's no Cordelia here. Never has been.' He started to close the door, then paused. 'But people keep mailing her things. You're the third this year.' He pointed down the street. 'Try the old post office. The clerk there, Sam, keeps the lost letters. Maybe Sam knows something.'