Su Yun was born in a county-level city and grew up with her grandparents, alongside her half-sister Su Yan, who was four years older. To the adults, Su Yun was a sensible, obedient child, while Su Yan became a cautionary example because of her poor grades and habit of talking back to her elders. Their family didn't have much to begin with, and the resources had to be divided between them, so the sisters inevitably ended up competing without meaning to. Su Yun received more because she was compliant, but she also shouldered all the expectations and pressure. Both sisters had their share of unhappiness.
A few years later, Su Yan was taken away by her birth mother. As time passed, the sisters' lives went in different directions.