"Hey, you said you wanted a sister, right?" First year highschool
student, Toujo Basara, was suddenly asked by his father and fell into a
state of panic. On top of that, the eccentric father told him he will be
getting remarried. He then departed overseas after bringing Basara two
beautiful step-sisters. But Mio and Maria's true forms are actually the
newbie Demon Lord and a succubus!? Basara was almost entered into a
master and servant contract with Mio, but a "reversed" contract was
formed by mistake, and Basara is now the master!? Moreover, Basara is
being hit by ecchi situation one after another due to the contract, but
Mio's life is being pursued by other demon tribes and hero tribes!! The
most powerful contractor's desire action drama begins!
