What if a man and a woman who missed the last train experience "mixed-gender onsen scrubbing"!? What happens if two men and women who are not lovers or sex friends soak in the hot spring and wash each other's bodies while slightly drunk!? The distance between men and women touching each other naked gradually narrows... Simultaneous arousal... In the bath, in the shared room, will men and women cross the line and repeatedly desire each other raw...!?