My Fake Wife Is A Genius Doctor

Her adoptive mother's last wish was that she go back to the Gu family, so she goes, and she leaves her talents out of the introduction. As far as the household knows she is an unremarkable young woman with no particular use. The adopted daughter starts on her immediately and keeps at it, and the family agrees out loud that she could not be trusted with anything important. She does not argue. She handles what comes at her quietly enough that nobody notices it being handled. Then she saves the Huo family's grandfather, and Huo Yuan, who runs that family and has a reputation for not being sentimental about anyone, starts paying attention. What was supposed to be a broken engagement becomes a fake one. They circle each other, then work together. He puts shares in her name; she puts herself between him and things that could kill him. The arrangement holds until her real identity comes out, at which point both of them find out what they have actually been to each other.