Take one part roleplaying game, one part dating sim, and one part mystery-solving, set it in a traditional elite girls' school, and you'll have Hanako Games' Black Closet, a slightly rough but engaging twist on more than one genre.
In Black Closet, you play the student council president at an elite girls' school. Your job is to chase down scandals, maintain the institution's integrity, and keep everybody—especially your student council minions—happy.
This is a pretty unenviable position: Take too light a hand, everyone runs roughshod over you and the school loses its reputation; too forceful and it's bad karma, making your fellow students like you less. Interestingly, there's the added twist that one of your minions is out to betray you, and to find out who that might be, you'll have to get to know them better, perhaps even romantically. And there's only so much time.
Most of the game involves solving cases by pairing your minions off against other students or locations, with statistics like stealth, observation, intimidation or social grace generally determining their success or failure. In between cases you visit and spend time with the other girls on student council in visual novel-style conversation menus. You're trying to find out who might betray you, but you can get into relationships with them, too.
Hanako Games is also the publisher of the excellent, brutal princess sim Long Live the Queen, and compared to that game, Black Closet is visually disappointing -- it has a rougher handmade feel and is not as well-illustrated, and while the mechanics are simple, players have to feel them out a bit intuitively, as they aren't well-explained.
But after playing the demo I'm kinda digging it it—the concept is engaging and offers a refreshing take on games where you manage teams. The mysteries are randomly generated, so each playthrough will be different, too. If you're into that kind of thing, a generous demo is free and available to try at Hanako Games' website.