New recruit at SOD's sales department, Yuki Mizuno, has just joined the team. Her petite stature and youthful face make her quite popular among colleagues. Although she can be a bit ditzy and naive, she possesses an abundance of energy and enthusiasm. When some male co-workers learned about her innocence, they decided to take advantage of their time during an internal training session by secretly filming her first sexual encounter. The resulting footage captures both her initial embarrassment and genuine passion, leading them to rush its release under the title 'Debut'.