A humpback whale is 40 tons of mystery. These giant creatures range from their feeding grounds off southern British Columbia to the waters around Hawaii, where they winter and breed. And every year, Dr. Jim Darling follows them as they travel through their ecologically fragile habitat.

Until Jim Darling came along, scientists who wanted to study whales killed them. Darling turned whale research upside-down in 1971 when he began tracking whales and their sounds with underwater microphones, and using photos to identify individuals. He brings incredible passion to his study of some of the most spectacular creatures on the planet.