Fed up with being hopelessly single, high schooler Erika makes up a boyfriend to fit in. When her lies start to unravel, her schoolmate Kyoya offers to be her pretend boyfriend--for a price. With no other choice, Erika finds herself at the mercy of a blackhearted prince! But is Kyoya truly as blackhearted as he seems?

Summer break is finally here! Erika is in full romance mode, making plans to spend time with Kyoya, when Kyoya's big sister appears! Suddenly, Erika finds herself in Kobe with the Sata siblings to meet their mom. Will Erika survive being with the Sata clan under one roof?