In the middle of the thirty-first century AD, human civilization has collapsed.
What was once a bustling city with bustling traffic is now nothing but a rotten steel and concrete skeleton;
The forests and oases that once covered the earth have now turned into dangerous wastelands.
Five hundred years of Great Recession and three hundred years of Dark Ages.
Human beings have long forgotten the stars above their heads, and have gradually lost the meaning of their own existence.
There is only one thing left engraved in the bones and blood:
Stay alive.
In an unknown wilderness, there is a small settlement called "Watch".
There lived a pair of fatherless and motherless sisters.
Sister Lida is a bone digger who goes deep into the ruins of the old world every day, just to search for relics that can be exchanged for food and clean water.
Sister Lier is a farmer. While taking care of farmland, she cultivates mutant crops, trying to select high-yielding varieties that are suitable for the new environment.
The sisters' daily income is barely enough to make ends meet.
They could have lived an ignoble existence like this, grown up slowly, and eventually become ordinary village women.
Or die quietly in some crisis at the end of the world.
But one day, Lida discovered a foreign object in a white old-era building.
From then on, they were forced to leave their hometown and enter the inaccessible wilderness.
On the devastated land, these two unknown sisters embarked on their own adventure.
