This is the ultimate sadomasochism setting of "two-way rebirth + time closed loop + repeated game". In the last life, Gu Shi'an killed Lu Xingzhou with his own hands in order to comply with his last wish, and then burned the entire laboratory with his body, and the two died together. But because they both died before the virus spread, the timeline was forcibly restarted to the point where everything began. Now both of them are back with complete memories, and both think the other doesn't know. One wanted to make amends and tried his best to stop Lu Xingzhou from getting the virus sample; but the other knew that "if I was not infected, there would be another way to destroy the world", so he cooperated with Gu Shi'an on the surface to act affectionate, but secretly continued to implement the plan. The two people fell into a crazy push and pull in the lie of protecting each other - he thought he was saving him, and he thought he was saving the world. It was not until he discovered that the other person was also a reborn person that he realized that in fact they both just wanted to die for each other.
