Sweet Yun Hwa reluctantly becomes the heartless step-sister of Yu Ra. Although Yun Hwa never wanted to be siblings with Yu Ra, she later realizes that it wouldn't matter, as a difficult situation arises where her long-time boyfriend, Yun Jae, coincidentally becomes Yun Hwa's pitiful boyfriend. In a tragic moment, Yu Ra takes away everything Yun Hwa ever had: a promising future, a loving boyfriend, and the comfort of her family.

Yun Hwa's life takes an unexpected turn when she becomes the step-sister of Yu Ra, a heartless and manipulative girl. Despite Yun Hwa's initial resistance, she soon realizes that their relationship is inconsequential. Fate intervenes when Yun Hwa's long-time boyfriend, Yun Jae, unexpectedly becomes her pitiful boyfriend. In a cruel twist of events, Yu Ra seizes everything that Yun Hwa holds dear: her promising future, her loving boyfriend, and the solace of her family.