Hitomebore to Iwa retanoni Jitsuwa Otorida to Shitta Hakushaku Reijou no Mikkakan

Grace, a poor countess, was supposed to be happily married in three days to the high-class nobleman Duke Ansel, who professed to have felt "love at first sight". But she overheard Ansel saying "It would be awful if we just got married like this!" Apparently, she is supposed to be the bait to draw out a hidden villain who was threatening the duke....