Kō Kitamura, whose family owns a sporting goods store, has known the Tsukishima girls since he was born. The Tsukishima family runs a batting center and cafe, and they have four daughters. There's Ichiyo, the responsible eldest; Wakaba, Kō's cheerful best friend; Aoba, who doesn't get along with Kō; and Momiji, the energetic youngest daughter. When Kō enters high school, he aspires to lead his baseball team to the Koshien National High School Championship as their ace pitcher and make Wakaba's dream come true.

It's approaching World War 2 and China is expecting to be invaded by Germany and Japan. Mr Ang is hired by a Chinese group who are after a "secret document." Many other groups want to get their hands on it as well. It's on the top floor of a tower and Ang must fight his way to the top.