Mio, a call girl, is not getting enough customers and is on the verge of being fired! The manager also criticizes her for her blowjob training, and she thinks she's at her limit... But then the manager's father, Yuji, shows up. He takes Mio home, saying he'll train Mio to be the number one girl, and the two of them end up living under the same roof. You'd think he'd teach her some secret technique, but he doesn't. But that was just the first step in Yuji's training plan!