Lost letters have only one hope for survival . . .

Inside the Dead Letters Depot in East London, William Woolf is one of thirty letter detectives who spend their days solving mysteries: Missing postcodes, illegible handwriting, rain-smudged ink, lost address labels, torn packages, forgotten street names - they are all the culprits of missed birthdays, broken hearts, unheard confessions, pointless accusations, unpaid bills and unanswered prayers.

When William discovers letters addressed simplyto 'My Great Love' his work takes on new meaning. Written by a woman to a soulmate she hasn't met yet, the missives stir William in ways he didn't know were possible. Soon he begins to wonder: Could William be her great love?

William must follow the clues in Winter's letters to solve his most important mystery yet: the human heart.