Yakuin Jirou a third-year High-School student hopes that he will get his first love from the same class Sakurazaka Shiori as practice partner in his High-schools mandatory "Couple-Practical". In this practical, students have to demonstrate that they have the necessary skill-set to live on their own with a partner of the opposite sex while presenting a certain level of harmony to the video surveillance that grades them.
Unfortunately random chance put his slighty subdued self into the practical with the person most opposite of him, the Gyaru Watanabe Akari. Akari on the other hand hoped to be in the practical with her crush Tenjin Minami instead.
Their hopes are doubly dashed when they find out that Shiori and Minami were assigned together, so they decide to reluctantly cooperate to receive an top ten rating which gives the top ten couples the right to exchange partners if both couples agree. To that end Jirou steals Akari's first kiss on the lips without realizing what he'd done, while giving a hurried good-bye kiss...