Michi and her family have just moved into the Happiness House, a massive tree featuring various small structures built on and within it. While exploring her new bedroom, Michi discovers a peculiar, nut-shaped object. Shortly thereafter, a strange creature named Nanami-chan hatches from it. The two quickly become close friends. Together, Michi and Nanami-chan learn all sorts of new things, and each day they encounter more eccentric residents of the Happiness House.