Spelunking in Texas, the Kratts explore America's largest bat cave where more than 20 million Mexican free-tailed bats have made their colony. Using breathing apparatus while navigating mounds of bat droppings, the brothers camp inside to live with the nocturnal species on their turf, and are there as a new generation of bats is born and opens their eyes. The Kratts watch these young bats mature to the point where they can fly, using echolocation to emerge at sundown amongst the huge swarm.
