Sakagami Sakura and Momiji are high school girls at a certain school. One day, the two overhear the boys whispering about them—calling them the "Iron Maidens." Frustrated and unsure how to respond, they turn to their longtime classmate Eiji for advice. "Ugh, a playboy like you wouldn’t get our problems anyway." "If you’re not into it, just brush it off." "But we are girls our age, you know. It’s not like we’re completely not interested..." "Then, wanna give it a shot?" Though hesitant about Eiji’s wild proposal—a 24-hour sex marathon—Sakura somehow finds herself agreeing, and Momiji follows suit. Joined by Eiji’s upperclassman, the delinquent Seigi, the Sakagami sisters end up at a love hotel with the two boys. At first, Sakura and Momiji are stiff with nerves, but under the boys’ experienced touch, their resistance melts away. What begins as awkward and painful soon transforms into waves of overwhelming pleasure—and their 24-hour session spirals into an endless climax.