The ancient Firth River winds across a vast glacial refugia ringed with dramatic mountain peaks and rugged expanses of tundra flowing northward to the Beaufort Sea. Yet for all of its inherent beauty, the Firth's greater value is as the sole means of access to the isolated summer home for 120,000 caribou of the West Porcupine herd. Migrating in small bands, the caribou congregate in coastal calving grounds before moving in huge herds across the Firth River.