Otatsu serves as the mother-in-law to Eikichi, the leader of a traveling musician troupe from Ōshima Island. She journeys alongside her son-in-law Eikichi, her daughter Chiyoko (Eikichi's wife), her 14-year-old granddaughter Kaoru (Eikichi's sister), and a maid. Acting as the matriarchal figure, she oversees the troupe's engagements and interactions during their travels across the Izu Peninsula.

Belonging to a social class of itinerant performers historically marginalized in pre-war Japanese society, Otatsu possesses a protective awareness of societal boundaries. She extends hospitality, inviting the student narrator to visit their home during winter holidays, showing openness to those kind to the troupe. However, she enforces strict social boundaries, forbidding Kaoru from accompanying the student to the cinema. She explicitly cites the class disparity between a "Tokyo student" and a "minstrel girl," demonstrating her understanding of societal hierarchies and commitment to shielding Kaoru from potential exploitation or rejection.

Within the expanded narrative of the 1933 film adaptation, Otatsu participates in a subplot concerning the loss of a family gold mine due to Eikichi's carelessness. She navigates tensions arising from Zenbei's proposal to "spare" Kaoru from the performers' life by offering financial security through marriage to his son Ryūichi. This storyline emphasizes her familial responsibilities and concern for Kaoru's future stability, while the film obscures explicit class conflicts in favor of nostalgic themes.