Kohitsuji-tachi no Rakuen

A peaceful town "Uraisgau" where magic coexists with steam engine technology. For the last years it focuses on education to improve sacred magic skills through studying technology. The best students become Holy Knights, but on a peaceful continent it becomes a honorary profession.
This year there are a lot of problem students, including main character who can't stand theology, but has to obey his uncle priest.
A new transfer student is an oriental girl Aina who comes to study other types of technology. She invites protagonist to her study group and says they already know each other from the childhood when they were separated...

[From vndbreview]