The middle Mitchell triplet, known for her photographic memory and organizational skills, which make her the unofficial librarian of the town after the library closes. She has a strong preference for the color yellow, which influences her actions throughout the story.

The youngest triplet, who has idioglossia and uses a voice app to communicate; she possesses a level of intellect nearing genius and demonstrates profound emotional insight. She takes over the defunct town newspaper as her form of expression and engagement with the community.

The mother of the triplets, who works as the town therapist and bartender, embodying community spirit and leadership in Bourne. She leads the charge against Belsum Chemical, seeking justice for the environmental damage caused to the town.

The town’s clergyman and physician who provides various essential services to the community. He helps guide the young people of Bourne with wisdom and compassion.

The town mayor who is dedicated to the welfare of the community, sometimes making unpopular decisions for the perceived benefit of Bourne. He collaborates with Nora in her investigation into Belsum Chemicals.

The son and grandson of the owners of Belsum Chemical, initially an unlikely ally for the Mitchell sisters in their fight against his family's company. His charm and intelligence make him a romantic interest for the Mitchell sisters.

An executive in Belsum Chemical and a key antagonist, he represents corporate greed and environmental exploitation. He is manipulative in both business and personal matters related to Bourne.

Nathan’s wife, whose family sold land to Belsum Chemical, contributing to the environmental crisis in Bourne. She shares her husband’s values of prioritizing profit over community welfare.