Rising to the Top While I Marry As A Widow

The girl had been mistreated by her family since childhood, and the general was originally engaged to the woman's sister, but because the general was assassinated, the family forced the woman to marry in place of her sister. But in reality it was all a ploy by the emperor and the general, because they wanted to fake their own deaths to bring out who was behind it. What happens when the girl fulfills her promise to be a widow at the general's house? Will she be able to unravel the truth?