Based on the manga of the same name by Ima Ichiko, Ritsu is the grandson of Iijima Kagyuu, a novelist who wrote about supernatural phenomena. From his grandfather, Ritsu inherited the ability to see ghosts, demons and spirits. Thirteen years ago, Ritsu's father, Iijima Takahiro passed away and miraculously came back alive. Only Ritsu knows the truth: a demon named Ao-arashi entered his father's body and brought it back to life. Since then the demon has been living as Ritsu's father. It made a promise to Kagyuu that it would protect Ritsu until his eighteenth birthday. After that all bets are off. Ritsu's eighteenth birthday is coming up soon. What will happen then?