Kong Ling traveled through time inexplicably, and then a certain system said that you must complete my mission before you can go back. Otherwise, you must stay at the place where you last traveled and never go back. Kong Ling's heart was broken. She wanted to escape, but the system lingered on. In the end, she discovered that this was her previous life.
(The introduction is all nonsense, because I always don't play by the rules, so please forgive me for this inexplicable introduction.)