Rena received a special offer to become the secretary of the chairman of a certain company, attracted by the high treatment. She was stimulated by curiosity about the unknown area that she would never experience in her daily life. However, it led to an unexpected development that betrayed her sweet expectations. What began was a secret training that could not be measured by common sense. "Something is wrong..." Although she felt that way, Rena tried to cut it off as work. But day by day, her heart and body changed involuntarily.