Kayano is the future head of the Madenokouji family, and has been raised completely sheltered from any kind of mention of love, sex or the opposite gender. She is even forbidden from approaching young men. However, she becomes intrigued when she hears her fellow students talk about "romance".
Her clan, stablished in the 8th century, has forever protected a mystical tree called "Kusunoki-sama". Legend is that if you pray under it, the world will stay peaceful and the clan's life will be preserved.
However, Kayano's life is turned upside down the day before she meets her fiancé. She had a strange dream where a voice inside the mansion tells her to enter a mysterious room, and there, she finds an old notebook... and a boy comes out of it!
"Call me Kussun. I'm the soul of this book. Anything you write in here will come true".
Kayano, filled with curiosity, starts filling the notebook with all her wishes. Meeting her fiancé, getting a handsome new tutor, and becoming entangled with young men she wasn't even allowed to imagine a few days earlier... The protagonist's new mysterious life with this magical book has just begun.