After the Golden Week holiday, Kokoro Kasai, a stunningly beautiful and naturally charming high school sophomore, transfers to Shimotsuki High School. With her striking looks and engaging personality, she easily handles even the most daring conversations with a smile. Aspiring to become the student council president, Kokoro soon attracts the attention of some troublesome students with bad intentions. However, what they don't realize is that Kokoro Kasai is actually a psychopath.