While shopping for some flowers in her local market, Tamako Kitashirakawa, the daughter of a mochi shop owner, encounters a peculiar talking bird named Dera Mochimazzi that decides to follow her home. As Tamako and her younger sister Anko go to the public baths later that evening, Dera has Tamako's childhood friend, Mochizō Ōji, take him to the baths as well. As New Year's Eve arrives, with Dera having put on weight after gaining an affection for mochi, Dera almost chokes on a mochi, prompting the neighborhood to help him out, overlooking Tamako's birthday.