Haruchika: Haruta & Chika

Haruchika (ハルチカ), also called Haruta & Chika, is a Japanese mystery novel series by Sei Hatsuno. Kadokawa Shoten has published five novels since October 2008. A manga adaptation published by Kadokawa Shoten in Monthly Shōnen Ace began serialization in December 2015. An anime adaptation entitled Haruchika: Haruta & Chika by P.A.Works premiered on January 7, 2016. A live-action film adaptation of the same name was released on March 4, 2017.

Plot
Haruta Kamijō and Chika Homura are members of their high school wind instrument club that is on the verge of being shutdown because there are only four members. The two are childhood friends that got split up but reunited nine years later, and they spend their days studying and also trying to recruit new members. When a mysterious event occurs within their school, they band together in order to solve the mystery.