Mysterious wife of arrogant CEO

A high school girl whose life changed when her parents died in a car accident. Her younger brother diagnosed with heart problems. She forced herself to do more partime work to pay medical bills until her maternal biological family came to her.

She was forcefully sent to overseas to complete her studies to takeover family business.But her miseries didn't held back .
She pretended her death only to return back to find herself being mother of a cute pair of dargon- phoenix of underworld king.
What happened her to become a mother ? Why she pretended her own death ?? Found out yourself while reading