Feeling self-conscious about his obese body, just at the right moment, a friend introduced him to a gym center that he had previously trained at very effectively, so the young man decided to come here in hopes of achieving a muscular and toned body. However, reality was not as he expected; the gym trainer Hatano and her colleagues proposed a very strange weight-loss method that left him extremely surprised - it was sexual intercourse. Nonetheless, he decided to trust and follow their requests, and every session he attended was 'training' under the guidance of a new female trainer. He could never have imagined that this center operated under the guise of deceiving gullible people like him, with the sole purpose of serving their sexual needs.