Otogibanashi de Himitsu no Kiss

The moment that Rio opens a book that she found by chance, she gets sucked into another world. There she meets a guy that she sees in her dream every night. His name is Tsukishiro. He's a magician who controls the story world, and his mission is to take a "princess" from the outside world there. He asks Rio to be act as the princess and complete the tale "Cinderella", however...