Taro, who has just turned 30 and is concerned about the excess fat around his stomach, is encouraged by his brother to get his sister-in-law Ayuka to work him out as his personal trainer. On the first day, Taro and Ayuka stretch together, and his crotch bulges out of his tight training clothes. Ayuka doesn't even look at Taro's crotch... A few days later, the two are sweating and training hard again. Taro's sister-in-law's coaching brings about changes to his body, but...