You know that feeling when someone's watching you? Petra Lindgren never had it. For eleven years, she lived her quiet librarian's life in Astoria, Oregon, drinking the same coffee, reading the same poets, maintaining the same careful routines that kept the world at a manageable distance.

Until the circulation report that changed everything.

Someone has been using her library card across the country—Chicago, Austin, Denver, Edinburgh. Someone who reads exactly what she reads, usually within days of her own selections. Someone who knows her literary soul better than she knows it herself.

That someone is dead now, found in Edinburgh's National Library with a book of Emily Dickinson poems and a face that could be Petra's own. Marion Voss—the sister Petra never knew existed, the twin who spent eleven years living in her shadow, collecting her discarded coffee receipts like religious artifacts and photographing her daily life with telephoto precision.

But Marion wasn't alone in her obsession. Someone else has been watching too, someone patient enough to follow both sisters across continents and decades, someone who understands that the most intimate surveillance happens through books.

The trail leads from surveillance walls in Edinburgh back to the basement archives of Petra's own library, where a man has been reading her Dickinson during night shifts for five years, counting his fingers while he cleans her office, and planning a family reunion that only one daughter will survive.

Some stories follow you. This one has been living inside your life all along.