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 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.