Nao Nao and Hong Hong are biological sisters. They are 4 years apart, but everyone thinks they look exactly the same. Honghong's sister is very proud of this, and Nao Nao's sister is very distressed about it. The two have almost the same body shape and height. The most amazing thing is that even their sweet voices are the same, so that the mother can't tell which one is the elder sister and which one is the younger sister.
Concept: Sisterhood is precious