After cleaning the Calligraphy Club room one afternoon, Kiryuu Keiki found a love letter addressed to him on the club's desk. Eager at the possibility of finally getting a girlfriend, he opens the envelope only to find the words, "I like you" along with a pair of the sender's panties. With only these panties as evidence, Keiki narrows down the identity to the four girls who helped him clean the club room that day: Tokihara Sayuki the lazy third-year president of Calligraphy Club, Koga Yuika a library committee member of foreign descent, Nanjou Mao, Keiki's slightly tsundere fellow classmate,