I know next to nothing about the series, but after watching the trailer it looks like it'll focus on a class of female spies and their relationships? With some focus on the male teacher as well, but he doesn't look like the average harem protag. That's just the impression I got from the trailer after looking it up, so I'm hoping it'll be a show that's at least good for shipping the female students together, and the male teacher is just a supportive character. I guess we'll find out if it's anything like that soon enough.