The End of the World, Starting from the Detention Center

Liu Yang, a senior mercenary in the apocalypse, was reborn a year before the apocalypse began. Seeing more and more awakened people popping up like mushrooms after a rain, Liu Yang just sat on the toilet and read the "Advanced Mathematics" tirelessly. "What can I do, I'm still in jail?" Liu Yang sighed helplessly at the surveillance camera above the cell.