Spoiler:
If my abysmal chinese is correct: Xu Ze's dad calls Tian Yu's dad because Tian Yu's phone is out of battery and discovers that Tian Yu's dad is his ex-bf from highschool. He previously mentioned to his wife that he had a bf in highschool but never went into detail about it. We get a flashback of their time together in highschool as he explains what happened to his wife...
Thats about the limit of my capabilities lol
What chapter is it?
https://toonkor.com/최강의-냄새