A private high school in modern Japan.

In this school where old and new buildings coexist, the Seven Wonders and strange rumors are whispered about daily.

However, in reality, most occurrences are just small events that are "slightly mysterious" or "a bit odd."

After school, Moka and the others naturally gather at "Cafe Maki" near the school.

They aren't exactly active as an official detective club.

It's just that Moka notices something mysterious, and everyone else gets dragged into it.