Despite her family's disapproval, Sakuragawa Miyako pursues her graduate studies at Eito University. Her academic goal becomes more interesting when she discovers that the prince of Estolia is also a student at the same institution. Miyako longs to befriend him for the sake of her research on his great grandmother, Queen Ritsuko. But the prince has different intentions, leading to a tale of sinful love where he claims ownership over her future.