A car accident turns Lucas Burton, the heir of Burton Group, into a 'fool'. His family marries him off to the jewelry designer Bianca Sutton. Despite never imagining marrying a 'fool', Bianca takes care of Lucas every day and gradually falls in love with him. Unexpectedly, Lucas's stepmother suddenly demands that Bianca marry her own son, bear a child, and seize the Burton family's property, mocking that Lucas is a fool who doesn't understand anything about relationships.