Mitsumoto-san, an office worker, is always suffering because of her kindness. But her hidden nature is that of a lewd sex monster! It all started with a prank from a colleague who noticed her hidden big breasts. "Mitsumoto-san, your breasts are surprisingly big, aren't they? Let me squeeze them a bit." These joking words stimulate her hidden nature, and the curtain opens on a sensual world filled with lust where she indulges in sex all night long...