Yukishiro Nanako is a cute, cheerful high school girl with one peculiar trait – instead of verbal communication, she writes senryu (a type of haiku) poems to relay her thoughts. Together with ex-delinquent Busujima Eiji, they are budding freshmen of the school’s Literature Club.

Even though Nanako doesn’t talk, with the power of senryu, the adorable pair has no problem enjoying their fun school-life through the tune of 5-7-5 syllables.

Nagumo Keeichirou was a genius high-school detective. No case was complex enough for him. But what happens to genius detectives when they get older?

Now 35, with bad hips, running a failing detective agency with no cases to solve and struggling to pay the rent, he's at a dead end.

In comes a high school girl in his office who says she wants to work with him. With her help, will the out-of-touch, old-fashioned Nagumo get back the fire of his youth?