Tantei Team KZ Jiken Note centers on sixth grader Aya Tachibana who worries about friends, family, grades, and more. One day, she joins the Detective Team KZ with four very unique boys that she met in cram school: Kazuomi Wakatake, Takakazu Kuroki, Kazunori Uesagi, and Kazuhiko Kozuka.

Source: MyAnimeList