My Time Was Limited So I Became the Villain’s Daughter in Law

I’ve reincarnated as the young daughter-in-law of a villain who was taken in for his deceptive plans. The problem is that I’m terminally ill, so I’m going to die when I become an adult. “Luckily, I know how to cure it, but…“ If I don’t die at the right time, my father-in-law—no, the villain, Duke Ecarde—might kill me just to achieve his goals!