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.

A submarine strikes a seamount just off North Korean waters and Mac must ask the Chinese for help. Meanwhile, Dickie's constant need for information has begun to irritate everyone. Meanwhile the first family deals with the question of reelection.

While trying to coordinate the rescue of the crew of a damaged U.S. submarine off the coast of North Korea with help from Chinese, Mac must deal with war fever among her advisors and a leak from China to the North Korean government that threatens to start a nuclear war. Meanwhile, Speaker Templeton’s wife secretly encourages Jayne Murray to accept Nathan’s offer to rejoin his office as chief of Staff.

Mac wants her Attorney General to look into an urban situation in Maryland because it's where Gardner is from. Mac is also briefed on the situation of the missing surface-to-air missiles that went down in a military plane crash over Pakistan and has to make sure that the weapons do not end up in the hands of terrorists. Templeton is ralling support for the Templeton Act which focuses on domestic crime and Mac is threatening to use her veto power in the hopes for more law enforcement and education over the bill's calls for tougher sentencing. Dickie learns that Vince is planning a commitment ceremony with his partner and he warns him not to invite Mac because it might hurt her in the polls.

On Mac's birthday, she is faced with the fact that there are American hostages being held in Turkey by a militant Kurdish group. Meanwhile, she also has to interview new candidates to be her Vice President and Dickie tries to convince her of the type of person she needs to choose because her choice will affect her re-election campaign.