One night, while Mary is working late at the bookshop, a shadowy figure leaves a box of books at her door. All of the books have beautiful covers clearly done by the same artist, and inside each book is an old letter addressed to a man named Jacob. To Mary's shock, the letters were written by her mother. The letters would simply be a sweet ode to young love, but the last letter hints at regret that could change everything Mary and Betty thought they knew about their mother. Who left Mary these books, and how did they get the letters?