All girls ninja school ~ yoga crest

Ichinose Kouta is transferring to the academy his grandfather runs. He knows little about it, except for the fact that the students are mostly female, so he imagines that his life will soon become a delightful harem-type story. When he gets lost on the way to the isolated school, he finds out there's a lot his grandfather didn't tell him. The school is actually an all-girls school for ninja!