While Bill and Dustin get close to a sow and 3 cubs at a fish weir, Dom races daylight on a long hike deep into the Chugash to find out what happened to one of his collared goats. Biology interns help band Alaska songbirds before the migration.

Chris Johnson patrols Tustumena Lake and faces glacial winds in Devil's Bay. Bill, Amber and Dustin hike deep into bear country and come dangerously close to several Kodiak bears. Laura and Todd discover a huge dip in the snowshoe hare population.

Chris rescues a sick eagle that's been dumpster diving at a local landfill. Laura investigates why an entire boreal forest has disappeared and transformed into grasslands in only 20 years. The Kodiak team gets up close to feeding bears.

On a research expedition, Bill and Dustin find themselves surrounded by Kodiak bears. Dom flies into the mountains to place tracking collars on mountain goats. John and the interns work to eradicate an invasive plant that threatens Alaska's waterways.

Officer Chris investigates a bear attack while Rob patrols the dangerous and remote outskirts of the refuge. Bill and Dustin head out to observe bears up close one more time before closing up their cabin for the season.