As Mackenzie begins the transition into the office of President, she has to select a Vice President, a situation in which Nathan Templeton tries using to his advantage. Mackenzie's daughter, Rebecca, faces a crisis when her diary goes missing, which contains information about her mother that could hurt her.

In the middle of the announcement of her new National Security Advisor, Anthony Prado, Mac is caught off guard by the breaking news of a terrorist smuggling explosives across the Canadian border. The way in which Mac and her Attorney General deal with the situation pits them squarely against each other, and Nathan Templeton takes great pleasure in publicly second-guessing Mac's every move. Meanwhile, it's Halloween, and Amy - who desperately wants to go trick-or-treating like a normal kid - is disappointed to learn that, due to security concerns, she may have to settle for a party this year instead. When Rod as First Gentleman finds himself fodder for late-night comics, it hits his son Horace especially hard.

When a destructive hurricane hits Florida, Mac and Templeton fly to Florida to survey the damage. While there, Mac learns of an emergency situation with an oil tanker off the Florida coast which could have devastating consequences. Meanwhile, Rod is seriously considering an offer to become Commissioner of Baseball.

When a tell-all book is published about Mackenzie Allen that contains confidential information suspicions arise. Meanwhile, the confirmation hearings for Vice Presidential nominee Warren Keaton begin, but raise questions about his past.

Mac suffers a burst appendix while aboard Air Force One. Since there is no Vice President in place, Templeton becomes acting President since he is the Speaker of the House and next in line. Meanwhile, there is an air strike that is crippling travel on Memorial Day weekend and Templeton ends up overstepping his bounds and handles the situation the way he wants to.

After a critic of the Equal Rights Amendment passes away and his wife takes over his seat, Mac believes she can amend the Constitution and pass the ERA once and for all. Meanwhile Templeton turns a Get Out the Vote campaign meeting into a presidential debate, Rod is asked to write a story about his relationship with Mac, and Rebecca finally learns the identity of her IM buddy, and both are shocked at just who the other person is.