Shounen wa Kouya o Mezasu

Kano Miyako, one of the famous trio at Asagi Junior High School, writes novels and always has a mysterious air about her. Kano, who writes novels and always exudes a mysterious atmosphere, is out of place in his surroundings, but he enjoys school life with Kanno, Kobayashi, and the three of them. However, it is exam season. In the midst of the reality of life, Kano meets Riku Koumijima, a young man who lives in Kano's heart. He looks exactly like the boy who continues to live in Kano's heart... The first volume of "Shaking Youth and Shadows".

(from mangaupdates)