In Episode 1 of Nee,... Shiyo, the story begins with a brother and sister whose playful interactions gradually escalate into something more intimate. What starts as innocent teasing and lighthearted moments between the siblings soon turns into a series of increasingly passionate encounters. Despite the taboo nature of their relationship, they find themselves unable to resist their growing attraction to each other. The episode explores their secretive and forbidden bond, highlighting the tension and excitement of their illicit connection.