After her older sister refuses to go to an arranged marriage meeting with Takane Saibara, the heir to a vast business fortune, high schooler Hana Nonomura agrees to be her stand-in to save face for the family. But when these two utter opposites pair up, get ready for some sparks to fly!

Summer's out, but Takane is so busy with work that he doesn't have much time to spend with Hana! Enter Takane's new assistant, Eiji Kirigasaki, an efficient helper who gains Takane's trust and allows Takane to have more free time. Despite all the support he's providing, however, Kirigasaki might have an ulterior motive that could lead to Takane's downfall!