Yotsuba&! is centered on Yotsuba Koiwai, a five-year-old[9] adopted girl who is energetic, cheerful, curious, odd, and quirky—so odd and quirky that even her own father calls her strange. She is also initially ignorant about many things a child her age would be expected to know, among them doorbells, escalators, air conditioners, and even playground swings.[10] This naiveté is the premise of humorous stories where she learns about, and frequently misunderstands, everyday things.[11]
