Traveling Through Cities Around the World, All People Enter the Era of Survival

In 2025 AD, "Return to Zero Day" arrived. Hundreds of cities around the world have been cut and moved by mysterious forces, and embedded in a strange prehistoric world. Modern civilization is scattered like broken biscuits in the primitive jungle, guns are ineffective and communications are interrupted. Qin Yi is a 24-year-old engineering boy. His parents died young and his only concern is his 18-year-old sister Qin Xing. The moment the disaster struck, he didn't panic. He just calmly confirmed his sister's location and then took action. He has only one rule: only do what is good for himself and his sister. The "learning system" is activated in his mind - learning knowledge to obtain points, which are used to upgrade the "initial space". From 10 cubic meters of storage space, to a shelter that can hide people, to a small world with soil and sunshine... While others are fighting for a mouthful of water, Qin Yi's space is filled with supplies; while others are shivering in the cold night, the brother and sister are sleeping soundly in a safe shelter. He doesn't have a holy heart and won't take risks for strangers. Everything he did was just to let his sister survive until the end. But the world is far more complex than imagined. More than one city was cut off, and more than one group of people survived. Some people are re-establishing order, some are claiming kingship and hegemony, and some are exploring the truth about "Return Zero Day". And Qin Yi's space is slowly growing into an independent world. Should we blend into this prehistoric era or create our own era?