Yosuke, wanting to change his weak constitution, transferred to the product development department of a fitness equipment manufacturer. One day, when he arrives at work just barely on time, he accidentally witnesses his boss Kana's secret. Realizing this, Kana decides to personally train him to prevent the secret from leaking. Yosuke can't resist her embarrassing and exciting Spartan training, and he continues to reach climax almost every day. However, as his body and penis are trained, his work also starts to improve...