Vivarium de Choushoku wo

Synopsis

The manga centers on three sixth graders, Yoshiki Obana, Mikoto Tajou, and Kikuri Kushida, who meet up at morning to get to the bottom of their town's "seven mysteries" as a free summer vacation project. After finishing one meeting at their "secret base," Yoshiki meets a mysterious ghost on his way home. (Source: Natalie, translated)