Ai is in love with a boy in her class named Tatoe. She thought she was the only one who was interested in him. But then one day at school, she sees him reading a letter that someone sent him, and everything changes. When she reads it, she realizes that he is secretly dating with Miyuki a gloomy girl who has diabetes. Ai’s love for Tatoe causes her to act rashly, and she decides to approach Miyuki without telling her how she feels. This is the beginning of a love triangle…