The Keefer brothers start their Alaska journey, seeking supplies with Glock 20s.

The Keefer brothers wake in a frozen tundra, forced to trek 8 miles without oars to reach their second cache.

The terrain changes as the Keefer brothers pick their way downstream, encountering a geographic choke point where predator and prey gather.

The Keefer brothers shelter in a small pine outcropping during a winter storm, conserving energy as they wait for the arctic blast to pass.

The Keefer brothers, low on energy, push downstream to find the next supply cache. They transition from open tundra to moose country.

With lifted spirits, the Keefer brothers set out to spot and stalk a herd of caribou near by, but closing in proves more difficult than expected.

With red meat, the Keefer brothers are finally able to replenish their depleted energy, but they aren't the only ones looking to survive the winter in the Alaskan wilderness.

The harsh reality of winter sets in, and the Keefer brothers are forced to sleep with one eye open as a grizzly patrols the area around their camp.

Racing ahead of an arctic storm, the Keefer brothers head down the river to their next supply cache. However, they get lost in the maze of small channels as the river divides.

As the temperature drops, the Keefer brothers battle through freezing water and headwinds downstream, aiming to reach the extraction site before the arctic storm arrives.

Chris and Casey Keefer recount their most memorable moments from this year's journey to Alaska's Brooks Range.

Chris and Casey Keefer share their favorite episode, and what it was like to experience it first hand.