Because Xi Nianli stayed up too late, he was a college student who was about to graduate, but he died suddenly before graduation. But it was accidentally bound to a system, She Xizhi (System, No. 69076449). Xi Nianli needs to travel through 4 worlds. As long as Xi Nianli survives until the end of the novel, the system will let her go out. That world will be completed, called the Messenger for short, but if it cannot be completed, he will be in despair in the end. (Don't worry, read the ending.)
Intention: You think you have changed everything, but in fact nothing can be changed