The Door Is Still Closed (2008)

Six people who had attended university together many years ago gather to enjoy a small reunion at a large mansion in the countryside. However one member, Fushimi Ryousuke, has an additional secret motive for attending this reunion. He must kill one of his classmates and he must do it this weekend. Taking into account the various features of the mansion, Fushimi comes up with a perfect plan that will ensure everything he desires. The unexpected arrival of Usui Yuuka, an underclassmen who had a crush on him in college, is just a small wrinkle that he will have no problem dealing with. Or so he tells himself.