Michi and her family start their new life in the Happiness House, a vast tree filled with miniature homes and buildings. As Michi explores her new bedroom, she finds a strange nut-shaped object that Nanami-chan, an unusual creature, emerges from. Michi and Nanami-chan form an instant bond and embark on a journey of discovery together. Each day brings new peculiar neighbors to the Happiness House for the duo to meet.