With her husband's business trip extended indefinitely, Ririka sinks into deep despair. One day, her son's friend, Kousuke, visits and she discovers he has been secretly watching her from her room. Tempted by his passionate advances, Ririka gives in to mischievous desire and can't resist seducing him. Soon, she finds herself repeatedly entangled in intense sexual encounters, continuously taken by Kousuke's youthful, insatiable stamina. Night after night, they copulate endlessly until dawn, leaving her utterly exhausted in both mind and body. Gradually, driven to the edge by his relentless fucking, Ririka finally reaches her absolute limit.