Yi Seo's quiet life turns chaotic when her mother remarries into one of the country's most formidable chaebol conglomerates, forcing her into a lavish yet suffocating mansion. There, she encounters Ji Seung-hyun, her new stepbrother, whose immaculate public persona hides an arrogant, deeply guarded personality.
From vicious dinner-table bickering to whispered late-night confrontations in empty corridors, hostility slowly gives way to magnetic, forbidden attraction. As high-society rivals scrutinize the family for any scent of scandal, the step-siblings must navigate corporate expectations without crossing a boundary that could ruin them both.
