You control character named 'Hailey'. One day, while planning a trip with her sister a rich man visits her farm. He told them about her father's debt and that he promised any of his daughter for marriage. Unfortunately he is missing for last 10 years so the sisters don't have any option but to pay the debt or marry that man.
Hailey refuses to marry him and tells him that she will pay the debt if he allows her some time. Seeing the opportunity the man tells her about her father's previous profession. He was a spelunker. During his early days, he found some secret treasure and hidden it away with the help of 20 stone keys in different mines. Those mines can only be accessed by anyone carrying his blood.
So the man makes a deal that if she brings that treasure to him, he will relieved them from the debt but there is one condition. They have to do it in one month.