With over 400 species of sharks, they don't all live in the warm waters of the tropics -- some inhabit the freezing cold waters of the Arctic. And who better to introduce viewers to one our planet's most unsung sharks than DIRTY JOBS' Mike Rowe, who travels north to the edge of the Arctic Circle in search of the mysterious Greenland shark. These large sharks are slow-moving behemoths, and learning more about them will help scientists understand the rapid ecological changes affecting that part of the world, and how the Greenland shark impacts the food chain there. Mike assists shark scientists with their research as they tag and release a large male Greenland shark. By the end of the trip, Mike gains a deep appreciation for the men and women who are studying this elusive shark in one of the most extreme climates known to humankind.