A former Broadway star and queen of the Washington social circuit, Didi Montgomery Mayflower, succeeds her deceased husband in the House of Representatives. Although she takes the job only to fill out her late husband's term, she soon sees that she can make a difference and becomes a force for political change. Didi speaks against a poll tax proposed by two of the House's most powerful members and decides to run for Congress in her own right, which causes a head on collision with her son in law, Marshall Bronson, who is also running for the seat. When Marshall tries to blackmail Didi, she exposes him on live television, goes on to win the election, defeats the poll tax and, through her daily appearances on the C Span network, becomes a national political figure.