There are 7,000 invasive species of plants and animals in the United States. Yes, we're being attacked. Who is fighting back? Well, meet Dr. Larry Gilbert who is leading the charge against the fire ant. At first we tried chemicals against this aggressive foe, but that didn't work. So, Dr. Gilbert has found a small fly that will hunt the ants down. Who else is out there on the invasive species frontier? What can we do to help in the fight in our own communities?