Naoya Mukai (voiced by Junya Enoki) is a male high school student with an extremely serious personality, so serious that it is a bit ridiculous. Since the first grade of elementary school, he has been deeply in love with his childhood sweetheart Saki Sasaki (voiced by Ayane Sakura), and confessed to her once a month, but all ended in failure. In a blink of an eye, many years have passed, and Naoya and Saki have both been promoted to high school. Finally, Saki agreed to Naoya's confession and became his girlfriend, which is really a cause for celebration. Who knew that not long after the two had just successfully dated, another girl in the class named Minase Nagisa (voiced by Azumi Kazuki) also confessed to Naoya. The serious Naoya couldn't avoid the inexplicable feelings that surged in his heart, so he made an outrageous proposal to Saki - he wanted to date Saki and Minase at the same time. What's even more shocking is that Saki actually agreed to Naoya's proposal.