They breed as much as 5 times more often than European honeybees. A single swarm can deploy an attack force of 80,000 stingers. Their armies of suicide bombers can chase an intruder for a quarter of a mile, and bring down a creature as large as a horse. Cruising at up to 20 miles per hour, killer bees have already overrun vast regions of South and Central America and pushed farther north than many scientists thought possible. Now, they threaten to invade the southern U.S., heading for both coasts of the country. Can scientists, beekeepers and exterminators stop the invading hordes before it's too late?