Mal Soon is a tough granny in a shantytown in Busan. In front of her, 12-year-old Gong Ju appears with her baby sister Jin Ju on her back. Gong Ju claims that she is the daughter of Mal Soon’s runaway daughter. Mal Soon’s peaceful life becomes a mess with these little strangers, but Mal Soon doesn’t feel bad living with them. Their happy-yet-unpredictable life under one roof is about to start!
Young Do, whose father was a merciless murderer, had to endure being called ‘monster’ ever since he was a child. His father’s dark shadow is constantly drawn over him despite his death by execution. Young Do vindictively lashes out to those calling him a monster, slowly becoming one himself. One day, a mysterious woman with a child shows up at Young Do’s house, claiming his father murdered her parents. When she demands his heart, Young Do points a knife at his chest, daring her to stab him. He eventually fails to kick the woman and her child out of his house, and adding to this, he learns of a secret of hers.