Laiyan is a vampire who has been trapped in the ancient castle for hundreds of years. He has long been tired of endless eternal life and is full of weariness with all things in the world.
Fu Yi has experienced the separation of life and death, and does not want to be held hostage by mortal life. He travels through dangerous places and breaks into the Yongye Castle, using his own blood as a bargaining chip to conclude a blood contract in exchange for immortality.
A transaction of equal value creates a two-way shackles.
He escaped the fate of death, but fell into the cage of eternal night; he had no care for the world, but he only held on to this hot obsession for survival.
In the long night, the two people are bound by blood and are shackles to each other.
Concept: The game of freedom and imprisonment, two completely opposite understandings of "living"