Last week, Iron Girls started their first mock triathlon competition for the first time in their lives. But even the first event of swimming is not easy to complete. Jin Seo Yeon is left alone at the swimming course with only 11 minutes left until the cutoff. What will happen to her? Iron Girls face various difficulties during the 40km-cycling and 10km-running courses. How will they deal with the unexpected situations and excruciating pains? Stay tuned to check out!