Houkago no Seijo-san ga Toutoi dake ja Nai Koto wo Ore wa Shitteiru

"Are you coming?" The time is 11:00 p.m. Yamato Kuraki, an ordinary high school student, is on his way home from the convenience store when he meets Sayla Shirase, a beautiful girl from his class who is known as a saint. She invites him to spend some time with her in the downtown area in the middle of the night, and that day is the start of a new relationship between the two. They play darts for the first time, lend and borrow CDs, and visit ramen shops... Yamato's boring daily life becomes more colorful as he gets involved with Sayla, who sometimes spoils him and has a mischievous side. "I'm really glad that Yamato came along with me at that time." This is the beginning of a sweet, precious story of youth and love spent with a saintly woman who is a natural in every way. (Source: Kadokawa, translated)