Under one roof unfolds a complex and heartbreaking relationship between a man and a woman. Discovering her husband's infidelity, the wife seeks to escape her loneliness by becoming intimate with her father-in-law. As love and desire intertwine, what fate awaits them? "I don't care anymore... just do whatever you want..." "Let's just go crazy and throw everything away!" Amidst swirling emotions, love and hatred entangle, giving rise to a new and intense drama.