My Childhood Sweetheart Breaks the Engagement, and I Marry His Family’s Bastard Instead

From the back cover

Everyone knows Scarlett is the woman Mr. Sterling chose for an arranged marriage into the Hayes family, and that whoever she weds will inherit the Hayes fortune. At the engagement party, her fiancé Derek Hayes pulls her adopted sister, Tiffany Peterson, to the center of the crowd and declares he will only marry her, leaving Scarlett publicly humiliated before the whole social circle.

What they do not know is that Scarlett's mother is the heiress to the powerful Vance family, and Scarlett herself will one day inherit that empire. Since Derek has made his choice, the Hayes heir must be someone else. When Mr. Sterling offers her other young men of the family, Scarlett points instead to Julian Hayes, Mr. Hayes's illegitimate son, who has long been disregarded by his own relatives.

Her father protests that Julian is a nobody, but Scarlett has her reasons, and Julian agrees to give it a try. As society fawns over Tiffany and the new alliance, Scarlett turns her attention to the task her mother has set for her abroad.