The protagonist, Mika, was sent into a different world and crashed into a garden of a rich person. Unable to pay her damages, she got enslaved as a sex slave. However, if after a short period, she is able to pay off the debt, she will regain her freedom.
Along the way, Mika also realizes that as she gets better, her slave rank increases, and enables her to satisfy richer customers that have a higher standard. With that in mind, she decides that her best course of action is to be the best sex slave.