Jougorou Kobato has a habit of inserting himself into other people's problems. After realizing his detective skills are neither wanted nor appreciated, he makes an agreement with his shy friend Yuki Osanai to become ordinary together. Now entering high school, they aim to be perceived as regular people, yet Kobato cannot help but fall back into his deductive ways when faced with everyday mysteries.

Unfortunately, mundane occurrences are not all the duo stumbles across. As they go through their school days trying to avoid drawing attention to themselves, Kobato and Osanai at times get caught up in incidents that put their plan of a peaceful, average life at risk.