This japanese movie talk about a group of high school girls in a trip with their (female) teacher victim of a group/pair of criminals that hijack the bus and kidnapped them abusing the girls and persuading the bus driver to help them in exchange of sex with the girls.

Some police characters follow them trying to save the girls and arrest the criminals.

There’s a lot of nude scenes but this is not a porn but a drama.

I think it’s from the 70s maybe early 80s an it’s a color movie I watch on TV subbed years ago (I’m from Italy).