Mackenzie “Mac” Allen (Geena Davis
), the 45-year old Independent Vice President, is about to enter a world in which no woman has ever stepped foot in before. While in attendance at a ceremony with her husband, Chief of Staff Rod Calloway (Kyle Secor
), Mackenzie is given the startling news that President Bridges needs emergency brain surgery to treat a brain tumor. Mackenzie is given an additional shock when she is also informed that in the event the President doesn’t make it through surgery, the party doesn’t want her succeed him.
However, despite sexist insults from both the dying President and Speaker of the House Nathan Templeton (Donald Sutherland
), Mackenzie decides to fulfill her duty as Presidential successor and take her rightful place as Commander in Chief of the United States of America.