Original plot, as its name implied, was the basic structure of the simulation. It was given to the transmigrator upon entering so as to aid their mission. Lu Yizhou had encountered hidden plots before so he was not too surprised to hear this news. On the contrary, he had an 'as it expected' manner. Only his lover was able to cause this kind of phenomenon.
Because Lu Yizhou was really curious about Pandora's real identity, he directly asked 666 to pour the plot into his mind.
Back then, the plot abruptly stopped at the point where Christian and Percy got to the Z-level.
Unlike Lu Yizhou, they were not able to hear Pandora's voice, so Pandora's hypnotic ability did not work on them. On that day, they encountered the mysterious bone skeletons in Z-level and realized that Pandora might not be what they had always been thinking about.