The Big C follows Minneapolis Westhill High School teacher Cathy Jamison – a reserved, suburban wife and mother – who is diagnosed with melanoma. The realization of this forces her to really begin to live for the first time in her adult life. At first she chooses to keep her diagnosis from her family, behaving in ways they find puzzling and increasingly bizarre. She finds new freedom to express herself. As the show progresses, Cathy allows her family and some new friends to support her as she copes with her terminal prognosis, and finds both humor and pathos in the many idiosyncratic relationships in her life.