Japan has entered a society with a seriously declining population.<br> The "Ikumono-gakari Law," enacted as a countermeasure to the declining birthrate, makes sexual intercourse obligatory, and boys and girls learn sexual acts at school.<br> However, the young boys and girls are so excited by the sex acts, even though they are in class, that they gradually escalate the situation...<br> They let their sexual desires take over, and the orgy begins!