After the fall of the Aztec Empire on August 13th, 1521, many surviving Mexica withdraw into a secret level of the underworld (Mictlan) to rebuild the culture without interference from the outside world. The god of war, Huitzilopochtli, then grants immortality to five warriors and eight designated intellectuals who are tasked with restoring Aztec culture while creating a harmonious, prosperous and unified planet. Their immortality is preserved by a well-guarded water source known as the "Healing Waters". Over the next five hundred years, the intellectuals anonymously integrate themselves into various cultures around the world to develop an understanding of technology, cultural development and languages, always returning to the underworld to share the knowledge with their society. Meanwhile, the warriors hone their fighting skills and prepare for their emergence into modern society. On the 500th anniversary of the fall of their empire (August 13th, 2021), the immortals emerge to discover a world that has been crippled by a Lassa virus pandemic. Upon discovering that the virus was created in a lab by a Russian Oligarch named Adrian Volkov, who is also manipulating and selling vaccines to the highest bidder, they decide to negotiate with him to help distribute vaccines to the most devastated countries. When Volkov makes it clear that he has no interest in supporting their cause, the warriors decide that his organization must be destroyed.