During a hot spring trip with three mom friends, they encounter a rude black tourist. Trying to teach him proper manners with gestures, they end up caught in a misunderstanding with the jovial black men who don't understand Japanese. They're then shown a massive, erect black cock, leaving them stunned. Despite their initial shock at seeing a black cock for the first time, their curiosity gets the better of them! They're captivated by the novel sensation and climax repeatedly.