A young Taoist priest inexplicably swaps places with someone and ends up in the modern era, living under another person's identity. There are no monsters causing trouble in this peaceful age, so he feels like he has nothing to do every day. Kind people feed him delicious food all the time, and he feels like he's put on a whole layer of weight. He resolves to do a good job at this new occupation.
Cheng Yu, who's a genuine hooligan pretending to be kind, accidentally brings home a young Taoist priest with an otherworldly air. Always a sucker for good looks, he coaxes him every day and occasionally comes up with ways to flirt with him. But a Taoist priest is a Taoist priest: he remains unmoved, much to Cheng Yu's frustration.
The top is purely attracted to good looks and doesn't care about gender. The relationship between the top and bottom may develop slowly, and there may be a little angst along the way.
In ancient times, the bottom was a sixteen-year-old Taoist priest. After inexplicably switching places and arriving in the modern era, he's still only sixteen. Since childhood, he's been taught to put the greater good and all living beings first. He doesn't cry, make a fuss, or threaten to hang himself. He's a taciturn type.
Warning: The top may not be a virgin (not sure, depends on how I feel later). The story depicts two different time periods.