Synopsis

The protagonist, after experiencing a traumatic event where he abandoned his sister, gains a system called the "Evolution Tree" which lets him evolve using points earned by defeating zombies. He uses the system to upgrade his strength and then reaffirms his vow to protect his sister Xinyue. He then faces a situation similar to the previous one when Miss Huang turns into a zombie, which causes him to protect his sister rather than abandoning her this time.