You remember the crazy scientist who kidnapped his Qizi's reincarnation just because he couldn't let go of him? Yes, this time he somehow let his Qizi's reincarnation slide outta his hand and escape, in a mini shuttle or something I believe. Ling Xiao's team then found this pitiful boy and tried to saved him, just when the crazy dude caught up on a massive mother spacecraft and demanded them to release his Qizi. To buy more time for the rescue, Ling Xiao took the boy's place in the shuttle and flied back to the scientist's spacecraft, just to trick him for a short time, ya know. There Ling Xiao got caught and detained. The person who supervised Ling Xiao's confinement on the mother spacecraft was our Principal's long lost Qizhu, tadaa. Due to his strikingly similar appearance to Ying Feng's, Ling Xiao would have mistaken him for Ying Feng had it not been for his juvenile body. However, at that time, Ling Xiao didn't know that the person was his Principal's motherfacca runaway Qizhu. On hearing the man's story about his disastrous and unwanted ceremony, Ling Xiao kept telling him to come back to Tianxiu, saying that his Qizi would be everlastingly miserable otherwise. Ling Xiao even mentioned the Principal's case with the man lmao. So that's how our Principal's Qizhu first went on stage, man. Later in the story they would reunite, and had a happy ending at that.