After Years Apart, Where Can Big Sis Run?

Wen Yishi and Liang Si grew up as neighbors. Later, for some reason, Wen Yishi moved away, and little Liang Si lost the one place where she could find shelter.

Years later, Liang Si sensed her older sister's presence again. She did everything she could to stay by her side, but her sister didn't recognize her. That's all right; we have all the time in the world, and a bright future ahead of us.

(There are some fantastical elements, but no cultivation, because immortals aren't allowed after the founding of the country.)