1. Extreme Justice

A trooper clashes with an intoxicated gold miner in the Season 4 opener. Also: a search-and-rescue mission for missing snow-machine riders.

2. Knife Fight

Snowflakes fall as Trooper Howie Peterson responds to a snow-machine accident where the victim may be dead or alive. As night falls, he frantically sets out into the backwoods of avalanche country to find the man. Then, a horrific stabbing sends trooper Blake Calhoun on a search for the stabber in a maze of unsecured cabins, where the potentially armed man could be hiding behind any door. Later, Trooper Anthony Stariha tries to catch a speeding vehicle before reaching the populous town center.

3. Alaska Chainsaw Massacre

Winter has seized Alaska, and Trooper Timothy Cronin gets a chilling call sounding like a domestic violence situation involving a chainsaw. But to get to this rural area, Trooper Cronin has to navigate through record snowfall. Then, Trooper Howie Peterson is greeted by a man at a cabin with a 15-inch knife and a rifle. Finally, Trooper Anne Sears responds to a crime against a village public safety officer and has to fly in unpredictable weather. Time to bring the rifles.

4. Shotgun Showdown

This episode starts with a bang as the troopers respond to a call about gunshots and screams. The hunt for the gunman leads them into the Fairbanks woods, where they find the suspect threatening to blow someone's head off. Then, on the waterways of western Alaska, the team must rein in some potentially volatile fishermen by both boat and float plane. Then, Trooper Stariha is hot on the trail of a fleeing motorcycle who suddenly takes the chase onto the crowded highway.

5. Armed and Bootlegging

6. Bloody Warrior

7. Campground Crazies

8. Grizzly-pendence Day

9. Hostage Standoff

10. Armed & Squatting

11. Meth Dealer Manhunt

12. Son and a Gun

13. Drunk and Dangerous

A trooper rushes to save a disabled man from a fire.

14. Fatal Inferno

15. Crystal Meth Compound

The troopers embark on a sting operation at the home of an infamous criminal who may be harboring stolen weapons.

16. Trooper Stalker

A trooper investigates a deadly fire in Alakanuk.

17. Deep Woods Standoff

A trooper must confront an erratic and hostile driver.

18. Blacked Out & Belligerent

19. Hot Drugs, Icy Streets

20. Too Much Pot

Patrolling the snowy streets and icy wilderness, as trouble comes armed and dangerous in the urban Mat-Su Valley with gunfight threats, kidnappings, and poachers.

21. Chopper Down

Wildlife Troopers Ernie Brent and Levi Duell race on snow machines against the time and the freezing temperatures to rescue a missing pilot.; Trooper Johnson is on a mission to catch a snow machine thief.