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 knew she shouldn't read more, but the first line had hooked her. She read the whole letter at her kitchen table. It was from someone named Theo, apologizing for leaving without saying goodbye three years ago. There was no return address, just a small drawing of a paper boat at the bottom. Wren felt like she'd stepped into someone else's life.

Wren turned the envelope over and found a faint postmark from a town two hours north. She typed the name into her phone and searched 'Theo paper boats.' To her surprise, a small bookshop popped up, with a folded paper boat as its logo. The owner's name was Theo. Wren grinned. She had a lead.

Wren almost drove up, then lost her nerve and mailed the letter back to the bookshop instead, with a kind note. She figured that was the end of it. But a reply came: Theo, thanking her, asking if she'd like a free book for her trouble. They began trading letters of their own, two strangers who'd both written to the wrong house.