I DDINT EVEN KNOW HE LEFT💀💀

These chapters are of them all grown up, after He Tian had an agreement with his brother that he would do some mafia stuff for him and then come back. When they wete younger He Tian left for a few years to do this, that's when Mo's heart was a little broken, then Tian came back (the chapter where he did was the New Year one)

So right now we are looking at the present (or future if you are looking at the manga as them still in highschool)

thanks I'll buy a beer