After Lyndon B. Johnson (Woody Harrelson) loses the 1960 Democratic presidential nomination to John F. Kennedy (Jeffrey Donovan), he agrees to be his young rival's running mate. Once they win the election, despite his extensive experience and shrewd instincts, Johnson finds himself sidelined in the role of vice president. But, that all changes on Nov. 22, 1963, when Kennedy is assassinated and Johnson is suddenly thrust into the presidency. As the nation mourns, Johnson must contend with adversaries as he seeks to honor JFK's legacy by championing the historic Civil Rights Act of 1964.