Fushigi Yûgi: The Mysterious Play.

Junior high school student Miaka lives a normal life in Tokyo until she finds a mysterious book in the library, and she and her friend Yui are transported the Universe of the Four Gods. Upon arriving in this new universe, the girls are immediately attacked by would-be slavers and saved by a dashing young man. When Miaka isn't looking, both Tamahome and Yui vanish. Unbeknownst to Miaka, Yui has been sucked back into the real world. Back in the library, all she can do is read on as Miaka sets out for the city to find the mysterious young boy and save her friend. But what awaits for Miaka isn't what either of the girls expect—and now Miaka's only way back to her world is to become the Priestess of Suzaku and save their world.