You and Airi have known each other since you were children, having studied together until college, where you separated when you decided to do your mandatory army service. After finishing your duty in the military, you returned to the city and got a job. It turns out that you found out that Airi was working at the same company, and you ended up becoming friends again.

Now, a year later, you and the girl are best friends once again, only you've developed romantic feelings for her, but you're not sure if she feels the same way. So you asked her out on a date, but she thinks it's just a casual thing between friends, and doesn't realize you're planning to confess or anything like that.

Now you have the mission to win her over, or at least make your feelings clear to her.