Astrid enjoys two things about her apartment organizing the Little Free Library outside the front doors and admiring her neighbor and crush, Grant. Talking to Grant, unfortunately, always makes her awkward and tongue-tied, so she doesn't try very often because it always ends in embarrassment. One cold morning, Astrid finds a little yellow thank you note inside one of the books in the Little Free Library. Intrigued, she replies, and begins a flirty correspondence with a secret admirer. It's not quite the same as a flesh-and-blood relationship, but on paper, she's far less nervous and much more herself. After a while, her newfound confidence even starts to improve her conversation skills with Grant. Everything is perfect—until Astrid offers to meet her correspondent in person, and the book disappears. Will she ever know who was writing to her? And has she lost her only chance at romance?