Zhang Si Nian (ML): The actor that portrays this character does very well with roles that feature him as a genius. But he was much better in Unforgettable Love (2021). The ML in the show was pretty nice but a bit slow on the uptake. Once he figured out that he was in love in the FL, he didn't play any games and tried his best to win her over.

Yun Shu (FL):
The Bad:
Childish character with annoying voice. I had to clench my teeth to keep going, because i just needed to know the entire story. I don't mind it when a character is a little bubbly, it makes things interesting, but Yun Shu was kind of unbearable. The ML looked better with Yun Shu's sister when they were all together in a frame.
The Good:
She was a nice person overall and also didn't play any games. She even reminded me of Shim Chung / Seo Hwa from The Legend of the Blue Sea even before she actually put on a mermaid costume.

It was an okay drama. Not worth a rewatch though.