Scientists believe that monster sharks make their home under the Old Seven Mile Bridge. Fishermen claim that one of the sharks is a 18-foot long, one-ton great hammerhead named Big Moe. If this is true, he will be the largest hammerhead on the planet.

In Australia, scientists have made an astonishing discovery: there's not just one population of great whites, there's two. And one appears deadlier than the other. Experts pit the shark tribes against one another to discover what's really going on.