I recently watched an anime called "When Cicadas cry", one i highly recomend and can be watched on youtube for free, and it has perked an interest in me in playing a murder mystery/thriller/horror game. I also admit, Persona 4 might have aided this as well, as the two are somewhat similiar. Both take place in small towns, both involve a small group of friends, and both involve mysterious murders, though in this regard they are fairly different.
As for a theme/story, I am flexible, but here is the idea i was thinking about. The game would take place in a small town. like a population of maybe 2000 people, so pretty small. I'd like the setting to be anime japan(What i mean by anime japan is that it would be japan, but charactors don't need to look Japanese. Ie, not all brown eyes and black hair, more like anime where having blond hair and blue eyes isn't really shocking), though once again, i am flexible about this.
basically, the town would be experiencing a bit of a boom. The towns massive waterfall has been chosen by the government as a means of electricity, so they are building a generator dam. While this in of itself isn't really hurting the town, save creating a bit of a lake, it also brought a lot of people to the town for it's contstruction. Not only that, howevr, but some large scale corperate business's suddenly seemed to notice the town and have began to, or already have, built some business's around and inside the town. The game might take place a year or two into the Dam's construction, where several large business's are already open.
Some people though, are not happy about the dam being contrsucted, not happy about the flooding of the land that will take place. Others aren't happy about the fact that these corperations are moving in and running many of the small mom and pop businesses out of business. This has caused an understandable amount of tension in the town.
My charactor will be new to the town, just arriving. He would be, i'm thinking, a highschool senior. Perhaps his father is a construction worker for the Dam, though he really could be anything. Some of the kids don't like him in his class because his father is part of the dam construction, but others don't seem to mind. Soon after his arrival though, their is a grissly murder, perhaps of one of the out of town people i'm thinking. The murder seems ritualistic, in some regards. Who did it is anybodies guess. Some say it's a disgruntled town member who was angry at the contruction, while some say it has to do with the forest spirits that are believed to have lived in the forest that will be flooded. Nobody knows. For one reason or another, perhaps bordem or another reason my charactor decides to try and solve the mystery. He might also have some friends to help him.
while i would be hoping for a one-on-one game, it's possible that a small group game could be made, though i think no more then four players, as the more players you get, the more likely the game would be bogged down. As far as erotic content goes, that in part depends on the players and GM, if it is a group game. If it's a one-on-one game, i could go for a straight up game, or a sexual game, but their has to be elements of a real plot here. Their does not have to be a supernatural element to the game, but their can be, or the killer(s) might simply try and make it appear that way.