Famine Falls into the Abyss

[OC worldview, slow-burning, partial group portrait, apocalyptic overhead worldview, the protagonist travels through] rift... The invasion of wild beasts led to the collapse of the old civilization. After hundreds of years of chaos, the survivors established the Spark Project and established a new order in the wilderness in the form of above-ground and underground cities. After a time-travel, Yang Jinyuan became the intern member of the A-139 team "Lin Wan"...