One Day, Hyun-Chae finds the most romantic note in the world inserted between the pages of a book in a library. The note leads her to another note, toward a mysterious man of her dreams. This note, however, is a real threat to Dong-ha, who has been secretly in love with Hyun-Chae for ages, but never said anything. Will Dong-Ha lose the opportunity to confess his love to Hyun-Chae forever, and will she listen to him if he does?