A six-foot alligator ends up dead inside the belly of a 13-foot python…it is the stuff urban legends are made of but viewers will have no choice but to believe when they witness the unthinkable. It's a battle nature never intended, but as a whole host of exotic species invade and multiply in Florida's Everglades, the ensuing battles seem to be increasingly pitting huge alien creatures against native apex predators. Everything from Burmese pythons to Nile monitor lizards are infiltrating Florida's swamp lands. Already, the aliens have breached the defenses and are marching onward inciting a ferocious turf war. Since 2000, more than 140,000 Burmese pythons have been legally imported into the U.S. as exotic pets. But these alien darlings soon become colossal, dangerous beasts and many owners find it easier to abandon them in the swampy marshes. Is there any hope for Florida's last bastion of wild paradise? National Geographic fuses science, forensics and natural history to deconstruct the bizarre encounter between a native gator and a massive Burmese python. Filmmakers recreate the grisly autopsy and work through tantalizing clues and at the story's climax, scientists use the evidence to reconstruct exactly what happened during that epic clash. Could an entire army of alien species be poised to conquer, kill and take over the Florida Everglades?