There is a door in everyone's heart. Some people expect to find the key, while others need a lock.
Cheng An later recalled the day he met Zhou Youyi. He got into trouble when they met. The dirty carrot head with no expression at all was loved by the Zhou family, which gave his originally emotionless childhood some memorable moments.
These clips are of Zhou Youyi's back when taking him to and from school, holding his hand when crossing the road, circling the camphor tree before the final exam... He has almost zero memories of his parents, but because Zhou Youyi likes his face, he is so lucky.
Cheng An probably couldn't become an upright adult, but because Zhou Youyi also pretended to be an outstanding young man. He thought he could still pretend for many more years, as long as the lock was still around, but the age gap and the consequent geographical distance scared him.
Purpose: To become a good young man with integrity for the sake of the one you love