On a late autumn evening. The sky was a little dark, and I didn't know what it was, indicating that disaster was about to happen. At the same time, in the delivery room of the hospital, a child was born. The nurse took good care of them and waited until both boys stopped crying before leaving. Just then, a strange gas fell from the sky. Entered the hospital and rushed into the boy's body. The boy was also frightened and woke up. When the nurse came in, she didn't notice anything strange, so she didn't pay much attention. This boy is the protagonist of this book.