As the ice road from Inuvik to Tuktoyaktuk is completed, drivers converge on Inuvik for the start of the year's transport season. Alex, Hugh, Rick, and Drew find themselves lumped in with the other "highway maggots" - the local drivers' term for rookies on this road - and must adapt to new rules and conditions. The road takes them up the Mackenzie River and over parts of the Arctic Ocean, with long stretches in which drivers are out of radio contact. Alex is delayed by the late arrival of Rick, who gets into an accident on his way up the Dempster Highway while bringing a truck to Alex. They are both dispatched to Mallik, a site of ongoing research into gas hydrate fields. As they take their first loads out (a boiler house and a drilling mud tank), Alex gets used to this ice road's higher speed limits (50 km/h or 31 mph and up), while Rick keeps driving at 25 kilometres per hour (16 mph) as he did in Yellowknife.

Word of Drew’s quitting spreads rapidly among the other truckers, but instead of going home, he finds work at a local moving company - driving a forklift at first, then a box truck. Eric is assigned the job of hauling a much-needed vacuum truck to Mallik; emergency repairs on its suspension and a frozen bolt threaten to ruin this plan, but he does eventually leave in time. Hugh takes a boiler to Mallik as Rick returns to Inuvik with a load of classified equipment from a Cold War-era military post. Six-year veteran Bear Swensen takes a load of rig mats to Mallik as Alex hauls a load to Tuktoyaktuk. On the way back to Inuvik, transporting contaminated soil, Alex spots emergency personnel attending to a flipped-over box truck whose driver is nowhere in sight. (Word later comes that this person made it back to Inuvik safely, while the truck is towed in.)

As the season’s first major blizzard closes in on the region, drivers scramble to deliver their loads before the ice road becomes impassable. With the help of a student trucker, Hugh takes his refurbished vacuum tanker to Aput, a natural gas exploration site, to haul away a load of wastewater. Drew makes his first ice road run of the year, bound for Tuktoyaktuk with a load of construction materials for a hockey rink, but his illness flares up and Kelly Brown (the senior trucker riding with him) has to finish the run. Rick is still off the road, waiting for a new oil pan to be flown in, as Bear hauls a drilling mud tank to Mallik. A snowplow gets stuck on the ice, but a repair crew quickly takes care of it.

The gas drilling wells at Aput have come up dry , so the entire operation is to be shut down and moved 50 miles (80 km) to a new site at Langley. Nearly seven million pounds of equipment must be hauled along the ice road as quickly as possible, in order to keep the company from losing any more money than necessary. Eric hauls a heat exchanger and a generator for the new site’s truck shop, while Hugh brings a load of rig mats up from Inuvik and later takes his vacuum tanker to Aput. Meanwhile, Alex takes a water tank and some boards from Inuvik to Tuktoyaktuk and Drew completes his first solo run over the ocean, hauling groceries to the same destination. Rick is once again off the ice, waiting on both an oil pan for his original truck and assorted repairs to the one he borrowed; Shaun and the other mechanics blame these problems on his rough handling of the trucks.

With the storm over and the road cleared and reopened, the truckers are ready to get back to work hauling equipment from Aput to Langley. To save time, rather than break the derrick down into pieces, Jerry loads the entire unit onto two trucks, hooked back to back with the derrick's ends resting on their trailers. Oncoming traffic is warned to yield the right of way to these two truckers; one convoy barely gets off the road in time, but the derrick still arrives safely. Eric hauls a cherry picker to the new site, once he and a supervisor get its frozen engine running again so he can drive it onto his trailer. Bear picks up an electric power station and carefully drives it to Langley due to its weight distribution.

Even though the derrick has been successfully moved from Aput to Langley, the crews cannot erect it until its 80-ton substructure is put in place. This equipment is split into two 40-ton loads and assigned to Alex and Bear. Alex has been battling problems with his health – hemorrhoids, shortness of breath, general fatigue – and Jerry holds him back for a while, sending Bear out first. The two loaded trucks have a combined weight of over 100 tons; Alex's load is the heaviest of his career. Both truckers stay below 25 km/h to avoid over-stressing the ice, and once they reach Langley, they must maneuver very carefully in order to unload the substructure halves in exactly the right position. Alex's half gets briefly tangled in the lines of one of the auxiliary trucks helping with the operation, but it is set down safely and the derrick goes up. Returning to Aput late in the day, he picks up a load of rig mats and crates, but Jerry keeps him there for the night out of concern for his welfare.

As the rig move enters its third day, there are still many loads to haul from Aput to Langley. While pulling a gas flare stack, Eric hears of a polar bear sighting near the road and makes plans to stay clear of the area, since several people have died in bear attacks over the years. The news quickly spreads among the truckers, and local wildlife experts equipped with snowmobiles and rifles are dispatched to ward off the threat. Bear takes a boiler onto the ice road, whose surface is now so rough that he makes a risky stop to check that his load is secure before proceeding to Langley.

With only a few loads left in the rig move, the pressure is on Jerry to finish the whole operation by the end of the day. He sends Eric out with a drilling mud pump and gives the last load to Bear—a tank for isolating and measuring the gas brought up from the drilling wells. Both truckers have to handle their loads carefully, and Eric’s low speed briefly causes a traffic jam that puts extra stress on the road. Once Bear pulls in at Langley, the rig move is complete and the crews hurry to get all the equipment assembled so they can start drilling.

Elsewhere, Hugh takes his vacuum tanker from Inuvik to Langley so he can drain the sewage tank again, while Rick hauls garbage from Tuktoyaktuk to Inuvik. Hugh has to be careful on the return trip; the battered road is becoming slippery due to the lengthening days, and the liquid in his tanker threatens to slosh around and cause him to lose control of the truck. Rick complains about both his truck’s condition and his own aches and pains, planning to see a chiropractor in Inuvik even though Doug wants him back in Tuktoyaktuk that night. He instead returns to the freight yard, intent on confronting Doug, and is surprised to be given time off for a checkup.

The time has come to dismantle the Mallik site, even as crews are close to a breakthrough on harnessing the region’s gas hydrate fields. When springtime comes, there must be no traces of any human presence on the site. Eric picks up a camp shack bound for Inuvik, with the goal of completing two hauls in one day. In Tuktoyaktuk, Rick and second-year trucker Bill Thorbourne are sent to Mallik together. Bill’s truck soon develops problems with its heater, and the two men have to nurse their trucks along so he does not suffer hypothermia or frostbite. Upon reaching the site, Rick picks up a load of dirty snow and Bill takes on an electrical generator and three lighting plants. They reach Tuktoyaktuk safely; before Rick can clock out for the night, though, he is put on loader duty and must unload Bill’s cargo. At Mallik, the crews succeed in extracting natural gas from the fields.

With less than two weeks to go in the season, the ice road is badly worn and getting thinner by the day, and every available trucker is called in to move loads. Eric and Hugh drive up from Inuvik, the former headed for the Wurmlinger to pick up a load of drill casings, the latter to Langley with his vacuum tanker to pump out the wastewater. As they return to Inuvik, Kurt climbs into an available truck and drives up to help in the effort, hauling back a snowcat and a survival shack used by the road crews. At the ice-locked Arctic Star barge, a headquarters for natural gas exploration crews, veteran trucker Jim Gattie picks up a three-trailer load to save time: two pairs of full fuel tanks and related supplies, all on sleigh runners. The strategy makes his drive especially hazardous, but he reaches the edge of Inuvik safely and stops to unload the sleighs so they can be dragged in one by one.

Now that natural gas deposits have been found at Langley, the top priority is to cap the well and move all the equipment out before the ice melts. However, the truckers must contend with both the thinning road and the water that has begun to flow up through the cracks. Rookie Devon Neff, making his first ice road run, and Hugh are dispatched from Inuvik to help with the job. Hugh picks up a load of rig mats and several large spools of cable, an unstable load whose weight distribution makes it difficult for him to keep traction on the wet, slick road. Meanwhile, just after Devon takes on two diesel fuel tanks and starts back, he is alerted to a severe water flow on the road directly ahead of him; he stops to re-secure his load, then proceeds slowly through the hazard. He and Hugh both make it back to Inuvik safely.

As daily temperatures continue to rise and the ice road keeps melting, Jerry works at full speed to clear all the equipment from the Langley site. Every available trucker reports in for the job, including Devon and Hugh; the former gets a camp shack, the latter a load of crates and pallets, and both start out for Inuvik. The site’s derrick is loaded onto two trucks, just as in the move from Aput, but the drivers encounter a serious break in the road and must wait for a pilot car to escort them around the hazard. They reach Inuvik safely, as does Devon, who runs across some severe overflows of his own.

On the final day of the season, there are still hundreds of tons of equipment to move within 12 hours. However, the road is now awash in water and literally crumbling away beneath the truckers’ wheels. In Inuvik, Rick seizes a chance to take one last load, a loader that is to be stored at Tuktoyaktuk until next year. Since he does not know how to run a winch, he builds an improvised ramp out of boards and tries to drive the loader up it and onto his trailer, without success. Rick’s supervisor, irritated by what he sees as Rick’s season-long lack of professionalism, fires him and threatens to have him arrested if he shows up again. The incident ends up with the supervisor swinging one of the boards at the cameraman filming the scene - narrowly missing him.

At Langley, Bear picks up a camp shack and takes it to Inuvik as his last load. Drew delivers a load of groceries and a couch to Aklavik, then heads home for the year, while Devon brings a camp shack back to Inuvik. He leaves with a measure of respect from the senior truckers for successfully navigating the late-season hazards.

The rivalry between Hugh and Eric continues as both roll toward Langley. Eric is slowed down by a surprise whiteout and a lull in the action on site, but eventually picks up some rig mats and storage containers and heads back to Inuvik. Meanwhile, Hugh brings his vacuum tanker up to offload some wastewater; once he has emptied the load in Inuvik, he sets out again to drain the last full tank. Both he and Eric had planned to pull two loads today, but the road is officially closed before Eric can pick up his second, leaving Hugh at the top of the load count. Jerry confirms that Langley is completely clear and clean, and Hugh — the last driver to come in off the road — goes home with Kurt’s respect for a season of hard work.

Final load counts:

• • Drew — 9; spent most of the season driving on pavement in Inuvik
  • Alex — 22 as stated in "A Trucker's Farewell"; left early for medical reasons
  • Rick — 51; fired on the last day of the season
  • Bear — 63; hauled a total of 4 million pounds, probably the most of any driver this season
  • Eric — 67
  • Hugh — 68