German spies infiltrate the United States successfully. President Kennedy is out visiting Utah, when suddenly, a Nazi on top of a grassy knoll sends a bullet straight through his head. Kennedy dies on his way to a hospital. Lyndon B. Johnson is sworn in as President just a few hours later. The investigation reveals the real culprits quickly.
Johnson has many choices. He could launch a massive attack on Germany for revenge, though that would be costly and near impossible to win. He could avoid a war, but the people would be upset at his inaction. Of course, he could call out for help, but who knows if anyone would answer.