Water backing up behind a dam is on the verge of wiping out a prime habitat for Nile crocodiles in South Africa. National Geographic herpetologist Dr. Brady Barr is on the case, doing what he can to help the crocs. It proves to be a harrowing adventure. Brady and his team must go by raft to get inside the gorge's high walls and over its rapids. With the help of Nile croc biologist Hannes Botha, Brady catches several huge crocodiles two of which measure 14 feet and attaches satellite transmitters to them. For the first time, scientists can follow a group of crocodiles faced with the loss of their home new and vital information not just for those concerned about Nile crocs, but for all who care about the effect of dams on our rivers and on the animals who live in them.