Yoon Jiwoo is both shocked and worried when her twin sister Jia drops a bombshell, saying that she secretly got married. Still, Jiwoo is determined to help Jia persuade their parents... until she learns that the groom's brother is her ex-boyfriend, Moonkyung. What's more, there's a complicated history between the two families. Now they must work together to resolve the misunderstanding and change their parents' minds. Will these unlikely allies successfully pull off this fraud and become family?