 The story focuses on fraternal twins Yori and Iku, who fall in love with one another despite being siblings and struggle to deal with their illicit relationship.The series is licensed for regional language releases in France by Soleil Productions under the English title "Secret Sweetheart", in Spain by Editorial Ivrea, and in Taiwan by Ever Glory Publishing.The original volumes were also imported to the United States and sold as is by Borders and Waldenbooks bookstores in early 2005.