The Answer was in...

"We can't find anyone named Xu Xin."

"Sorry to bother you. She entered school in 2003 and then transferred to another high school. Her name was Xu Xin. Can you please help to check one more time?"

"Sorry, sir. We have checked the entire's school enrollment information. There was no one named Xu Xin. I think you might be mistaken."

"Impossible. I found her data in our school's library and it said that she transferred to this school."

Xue Shao drove to the high school which Xu Xin attended as his head teacher suggested in the early morning.

"Sorry, sir. There is nothing we can help... I still have a lot of work to do. If there are no more questions, please excuse..."

Xue Shao left this school hopelessly.

He couldn't understand this weird phenomenon. Why did all the classmates and teachers remember Xu Jiayi and Xu Xin... but he didn't?

Why would he take these two girls as one person in his deep memory?