Kotoko Aihara, a cheerful but hopeless student in Class F, has admired the brilliant Naoki Irie since his entrance-ceremony speech. Her love letter is rejected flatly, and that same day an earthquake flattens her house, so Kotoko and her father move in with old family friends who turn out to be the Iries. Sharing a roof with the cold, IQ-200 boy she adores, Kotoko refuses to give up, and her persistence starts to wear on Naoki's indifference.