Houdzuki Maika is a high school girl who, in a way, is never alone. Her twin brother Maito, who died before they were born, lives within her and shares her life. They take turns living each day and share most of their memories. However, the only times they can see and speak to one another is when they are both asleep, allowing them to share the same dream. Perhaps as a result of this supernatural existence, Maika is able to see ghosts. In the first volume, the school counselor draws Maika/Maito into helping uncover the truth behind the disappearance of a female student whose ghost has left a message scratched into a classmate. There are surely many more mysterious incidents ahead for the twins to face!