The Three Sister's Became Goddesses

In a simple house, live three siblings with their loving father and mother. One day they did not expect their father to exchange them for another family, a few years later their mother remarried and they moved to another country to study well and live well, as they grew up they were loved by their stepfather and they accepted their stepfather as their real father. And the time came when they thought of visiting their grandparent's on their father Kyle's side and while they were in the bathroom of the airport they suddenly disappeared like bubbles as well as their belongings. When they open their eyes, Athena found out that this familiar place is the novel she had just finished reading and it was "The Cursed Prince's and The Saintess" In the original novel there are three demons who change form as a goddess and they are sisters. And what is more worrying is that they will act as the goddesses, will their lives be good? With their knowledge of this novel can they avoid death?