Kenzou Tenma, a Japanese brain surgeon in Germany, finds his life in utter turmoil after getting involved with a psychopath that was once a former patient.

Nakajima Youko is your average somewhat timid high school student. One day, a strange man named Keiki appears before her, swearing allegiance. Before she could properly register what was happening, demon-like creatures attack Youko and her friends, after which they are pulled into a different world. A world unlike what she has ever known. Separated from Keiki, Youko and her friends must do whatever they can if they wish to survive in this new world.

To get the money to pay for a doctor for his father, Romeo bravely sells himself as a chimney sweep. On the way to Milan he meets Alfredo, a mysterious boy on the run heading to the same fate. Upon being separated and sold to their new bosses, the two boys swear eternal friendship. Romeo has to learn the hardships of a chimney sweep's job.