Introverted childhood friends Akiho and Suzune have been dating for two years but remain virgins due to their extreme shyness. Their lives change when Sayu, a former introvert turned confident "Gal," returns and decides to provide them with "sexual training." With the help of other Gals, the couple overcomes their inhibitions and discovers a world of pleasure, eventually embracing a liberated and polyamorous lifestyle.
As Akiho and Suzune continue their sexual training with the gals, a popular classmate discovers a video of their activities. Rather than being upset, Suzune reveals that the thought of Akiho with other women excites her, leading the group into an intense session where she fully embraces her awakening depravity.