Emina Tokigawa, who is one of the main protagonists of this new series, enters Tsubame High with her best friends, Naru and Mana. While they are deciding on which club to enter, Emina states that she'll make her own new club: the Detective club. But as she entered the faculty roomso that she could register her club, she already had competition with four other students: Nana Mizuho, Miyu Hatoyama, Risa Naguri, and Shizuka Hanazono, all first years like her. This year, Tsubame has only one spot open, replacing the Cafe club from the previous year, which was the only club to resign. The four other girls else than Emina also wishes for this spot for the sake of their own personal clubs, such as Nana's Food Research club or Shizuka's Accesories club. In order to decide who gets the club position, Tomoe Miyashiro, the teacher who will instruct the to-be club, challenges the five girls. "Whoever gets 5 members to sign up will receive the spot for the club." Only by hearing this, the four other girls dash out of the room, as Emina is left behind.
All of the girls did what they could do, such as distributing leaflets or advertising their club. In the end, some part of their personality warded off all possible members. Back with Emina though, she remained calm. Later, in the faculty room, all five girls assembled again, reporting that none of them received a member. Knowing htat this would happen, Emina proposes to make one club together: the cafe detective club. All of the other girls are against this idea upon hearing the idea, but Emina is able to convince the four. Nana's cooking skills and Shizuka's sewing skills can be put towards the cafe while Miyu's Heroes knowledge and Risa's gaming can help promote customer entertainment. All agree, but before they finish with the club registration form, they change the name of the club from "Cafe Detective Club" to "Cahe Detective Club" as they noticed Emina's interesting 'weakness' of saying "he" instead of the "fe" in "cafe". Thus, the Cahe Detective Club has been created!