This drama tells the story of Ippei Omori, a bad man who is pushed to the edge of life and hates his family and children. In order to be elected as a member of parliament, he lives with his brother-in-law, a single father, and his children. In the process of facing family, social and Japanese problems in daily life, the worst man gradually establishes a relationship like a real family with his brother-in-law and his children, and gradually begins to want to create a better society. In the end, he seriously participates in the election and becomes a candidate. It depicts the struggle of "Japan's No. 1 Worst Man" to change his family, society and Japan.