Even though Kozue is just a brat, she thinks of herself as an adult and tries to act all grown up. These kinds of kids are the easiest to kidnap. If you say, "I'm a lawyer and my mom and dad are divorced," you can pretend to be calm and get into someone's car without a second Kokoro. Then, when you arrive at the parking lot, all you have to do is make her inhale poisonous gas. Her respiratory system stops working, and she faints, foaming at the mouth. It's really cute to see Kozue fainting, her eyes wide open as she is on the verge of death from the poisonous gas. A love story told entirely with poisonous gas.