Two Japanese babes, cousins from the same bloodline, engage in a taboo game of chance, the rules simple yet profound: 50/50 odds for either to pleasure the other. In their shared bedroom, they undress, their naked forms a mirror image of desire. One cousin, bold and adventurous, takes the lead, her hands and mouth exploring her kin's untouched flesh. They're caught by their grandmother, but the fire within them burns brighter, their game far from over.