One group drives the Dalton Highway, moving freight between Fairbanks and Deadhorse with occasional side trips to Nuiqsut and Anchorage.
She leads a convoy of heavy haulers, including Carey Hall, who needs her help to pull his own freight up a steep incline.
Dave's problem with shifting gears on the steep grades leads Tony to decide, at Prudhoe, that he needs at least one more escorted trip before doing runs on his own.
While taking a load of diesel fuel north, Tony stops at the site of his recent accident to pick up debris left by his truck.
After passing a drug test and taking a rough run in the trucking simulator, Maya spends a night relaxing at Chena Hot Springs in preparation for the start of her driver training the next day.
In Winnipeg, Hugh and Rick team up with another driver to transport the three sections of an airport terminal building to St. Theresa Point, 550 miles away.
Rick dents one of his rims on a bumpy stretch; by the time Hugh jury-rigs a repair job, the convoy has lost the whole afternoon.
In Garden Hill, Alex picks up a load of recyclable materials bound for Winnipeg and hears about the downed power line before setting out.
He barely misses two oncoming passenger vehicles, nearly spins out, and has his trailer come loose at night due to snow caked in the hitch.
He finds the Yukon River Bridge to be completely iced over and eases across, sliding badly before reaching the other side and arriving in Prudhoe that night.
A brief stop and under-hood check reveals nothing immediately, so Phil takes the wheel to see if he can hear it, leaving Maya disappointed at not being able to drive the entire run herself.
An exhaust leak into the cab sends the truck to the shop; once it is repaired later that morning, she starts the run again, ignoring disparaging radio talk from Dave.
Tony, hauling a load of explosives bound for Prudhoe, finds a truck in the ditch but does not stop to help due to the danger of his own cargo.
Finding miles of backed-up traffic due to the storm, he has to wait four hours until crews can clear a path to let trucks through.
It has sat idle for months and must be towed into the shop to get it running; she takes advantage of the delay to buy some equipment, including a knife for protection.
She gets a load destined for Anchorage, but gets a flat tire 50 miles into the trip as a result of pumping her brakes to melt built-up snow.
In Winnipeg, Hugh and Rick pick up fuel tanks destined for St. Theresa Point, but find themselves battling slick roads and hairpin turns.
In Fairbanks, Lisa gets a load of pipe sections that is so long (100 feet) that it needs a special rear dolly instead of a standard trailer to support it.
That night, they maneuver carefully past several southbound convoys and trucks parked on both sides of the road, leaving little room for error.
After stopping with Tony to scatter a trucker's ashes on the Brooks Range, Lisa goes south with a load of recyclable materials and hears about Maya's trailer problems.
Stopping briefly to help a driver fix a coolant leak, they meet Tony in Coldfoot during his Prudhoe run and discuss Dave's behavior.
He arrives in Fairbanks that night, an hour ahead of Phil; the next morning, his supervisors decide to take him off active duty until they can re-evaluate his driving.
Warming temperatures give rise to wet, slick road conditions, complicating the push to move the season's last loads.
In Manitoba, Hugh and Rick get an early start to move loads up to St. Theresa Point - concrete barriers and school supplies, respectively.
Alex, taking building supplies to Garden Hill, finds dangerously thin ice on a lake crossing and detours around it, adding 200 miles to his trip.
Tony picks up a load of scrap metal and goes south, passing a northbound truck as he reaches the point where he had his accident at the start of the season.
They have no success pulling loose until the driver returns with a second double-wide, providing enough traction to help move all the other trucks so Hugh and Rick can finish the trip.
He brings in his load and picks up a cargo of tools bound for Winnipeg; soon after starting back, though, he finds an antifreeze leak and must return to town.