As the new school term begins at Wakamiya High, shy bookworm Machi Tsukahara feels out of place in her lively class. One day, she finds a mysterious note in a library book with the word "Sakurasaku" written on it.
Machi, following her mother’s advice, responds to the mysterious letter she found in a library book, leaving her reply inside the same book. Will the original sender discover her response?