One day, after the son-in-law began living with his wife's parents, he found himself irresistibly drawn to his mother-in-law Aoi's huge breasts. Though Aoi initially treated him kindly, one day she could no longer suppress her passionate desires and aggressively pursued him. Soon, their relationship escalated into sex. Despite having previously resisted, Aoi became aroused by his presence and, taking advantage of her husband's drunken state, seduced her son-in-law while wearing erotic lingerie. Each step they took drew their forbidden bond deeper.