Mirabeau Lamar seeks nothing less than a Texas empire that will dominate the North American continent. Brave exploits at the Battle of San Jacinto bring him rank, power, and prestige, which by 1838 propel him to the presidency of the young Republic of Texas and put him in position to achieve his dream. Edward Fontaine, who works for and idolizes Lamar, vows to help his hero overcome all obstacles, including the substantial power of Sam Houston. Houston and Lamar are not only political, but personal enemies, and each man regards the other with contempt. Edward's slave Jacob likes and admires his master, but cannot share his hatred of Sam Houston. The loyalties of both Jacob and Edward are tested by President Lamar's belief that a righteous cause justifies any means necessary to sustain it. Lamar becomes infatuated with a married woman who resembles his deceased wife. He sends the woman's husband on the ill-fated Santa Fe Expedition, the failure of which humiliates Lamar and provokes a crisis in his relationship with Edward, who in turn jeopardizes the trust that Jacob has placed in him. Edward laments the waste of Lamar's genius, while Jacob marvels at the hypocrisy of both men.