The shapeshifting, prehistoric giant Tezcahtlip is free in the modern world, once more eating the hearts of victims to steal their forms, their memories and their power. After losing his brother in a battle with the American military, the giant flees to Mexico, taking up residence in the Yucatan where he poses as the Mayan god Kukulcan in an effort to gather followers, sacrifices and power. The men and women of Detachment 1039 will need help from an unlikely source before they head south to combat the monster. Can a vampire imprisoned at Alcatraz really be a help, or a hindrance?