Shuiqun, and Then Become a Magical Girl

Tenguin Sakuya's mother was the talker of the Tsuki no Mori family, but she suddenly died in an accident. In order to investigate the truth, Sakuya came to the Moon Forest and discovered that Toyokawa Shoko, the eldest lady of the Toyokawa family, killed her mother. In this world of magical girls, darkness is never allowed, not even in the Toyokawa family. It wasn't until later that Sakuya realized that the water inside was too deep...