The Nacom beckons Indy to follow him into the Underworld.
The Nacom was an ancient Mayan war leader that rose from the dead in the vicinity of Site R (in Mexico) during the mid-1930s.
Marcus Brody received news that the Nacom had enslaved a local tribe, yet considered it to be nothing but silly rumors and superstition. He asked Indiana Jones to investigate the situation and put an end to the rumors.
Indy discovered that the Nacom truly existed and that he could only be defeated with a special Aztec Sword. Jones claimed the sword and chased the Nacom into the Underworld (a barren volcanic area), where he finally defeated him.