Louis' neighbourhood bookstore has recently implemented a "Take One, Leave One" program, and Louis is delighted when the first book he finds is by his absolute favourite author. Wanting to return the favour to his mystery donor, he leaves the newest release of said author in its stead. When he returns the next week, the book is gone only to be replaced by another fantastic option - with a little note slipped in the front cover that reads simply "Loved your suggestion, hope you enjoy this one. -H xx". Wondering who this mysterious H is, Louis continues to leave books (complete with their own increasingly flirty notes) over the next few weeks, until one day he comes to find his newest option includes a note that simply reads "Meet here Friday evening, 6 PM?" It's a prompt fll. I wrote pretty much based on this.