Bai Jinge's father invented a space-time machine that allowed him to customize the space he wanted. Her father customized one. When Bai Jinge and her friend Shen Yizhou were trying it out, the machine made an error and they ended up in this time and space and could not get out.
In this self-defined time and space, they met Qin Muyu, the third prince of Cangwu Kingdom, and the story unfolded from there.
Sweet snippet:
Intention: Cherish the moment, no matter the outcome.