In The Case of Cecil...!?

(from ebookjapan):

Cecile, whose grandmother is the president of the prestigious St. Lily Academy and whose mother is the head of the school, hates men. The school has a strict no-men policy, and many of the students protested against the school culture. However, the boarding school, surrounded by high walls, is a safe and secure place for Cecile, who gets rashes at the mere sight of a man's picture. The wall separating the school from the neighboring boys' school, Barnard High School, is particularly high, sturdy, and reliable. However, for some reason, part of that wall has a hidden door...? "Leave Love to the Wind!" and "Viva! Shinigami-san" are also included.