A Story about a Girl who don't have any sibling. 

A girl insisting to accept her as a sister

A girl wants to have a mother.

A girl wishing to have a complete family.

What do you think will happen if Myungsoo hates her as a sister. 

and Myungsoo cant even accept her 'sister'. 

what if they unintentionally love each other.

what will happen if they live happily ever after or one of them will die.