In modern cities, the outside world and the inside world coexist. Ordinary people live under the sun and know nothing about supernatural beings; while the "Ninth Investigation Bureau", a national secret agency, is responsible for handling all supernatural incidents, covering up the truth, and protecting the world.
Gu Yan, a 24-year-old errand boy, accidentally broke into the scene of a supernatural incident late at night when delivering orders, and his hidden abilities were awakened. He was recruited into the Ninth Bureau and entered a bizarre world.
However, as his abilities grew, he gradually discovered that his life experience was far more complicated than he imagined. The mother's mysterious past, the father she has never met, the taboo experiment thirty years ago... All clues point to a secret called "The Other Side Project".
He is no ordinary investigator.
He was a product of that plan.
He is the key that opens the door to both worlds.
The person who created him was his biological father.
