Bai Bian Jin Zhi Xi Jiao Ji

Stunt double Yu Bei fell into a merman’s territory by accident. To stay out of trouble, she disguised herself as a princess. The merman prince, who had not seen humankind for a long time, suggested a marriage of state just so he could meet the human emperor and save his kind from exploitation. He then visited earth with Yu Bei but later fell into a trap that Yu Bei set up for him...

(Source: Bilibili Comics)