A Wife Secrifices

Oh Hayoung is a wife to one of handsome and tall man, Sehun. Oh Sehun is one handsome, tall and a billionaire that a girl would die for.
Both of them met at Sehun's company. Hayoung is the graphic designer and Sehun is the COO who will be taking his father place soon.
They were happy and love each other so much so Sehun propose to her and Hayoung said yes. Sehun's father and his elder sister, Seung Ah and his younger sister, Seung Hee loves her and treats her with love. What Hayoung didn't know is that Sehun's mother hates her and she has someone in her mind that is perfect for Sehun. So she starts to treat Hayoung badly and that will make Sehun and his father fight with his mother.
What happen when Sehun's mother fall sick ad wants Sehun to marry her chosen bride? Will Hayoung let Sehun marry her or will she fight for their love? On top of that, is Sehun's mother is really sick or she's just faking it?