Why Does the Plot Keep Flipping Over?

Gu Lanyin died and became a lonely ghost, wandering around the world with nothing to do. Suddenly he was picked up by a mysterious thing called the system, and was thrown into various worlds to follow the plot. But... "System, why don't the male and female protagonists follow the plot..." "Don't worry about it. The host just needs to follow the plot. If it deviates from the plot, they will correct it themselves." Later… "What should I do? After I got together with the second male lead, why did the male lead disappear? And what happened to the hole in the sky?" "No, the world of the host is going to disappear. Let's leave quickly." There are many questions about the system every day. Why does the host follow the plot so well that the world always collapses inexplicably? Why does it still lead the host to follow the plot without being destroyed by heaven when so many worlds collapse?