Kristen Shaw

Danny and Aiden investigate a brutal massacre of employees in a restaurant. Plus, an amputated leg is found in a rubbish bin.

Vice President Mackenzie Allen unites the nation in the wake of the president's death, quelling her critics, who wanted her to resign to allow the Speaker of the House to succeed to the office.

Nathan attempts to manipulate new President Mackenzie's first order of business, to pick a vice president.

Mackenzie faces her first national crisis when nine DEA agents are killed in Latin America; Nathan Templeton is offered potentially damaging information on Mackenzie's nominee for vice president.

Nathan Templeton plans to engineer a series of Cabinet resignations to overshadow Mackenzie's first official summit with the Russian president.

On the ground in California, a man holds Air Force One hostage and demands to speak directly with the president, or he will blow up the plane.