As the season 4 kicks into gear, the truckers take off on a 500-mile-long ice-covered road called the Dalton, encountering dangerous obstacles along the way.

Hugh "the Polar Bear" Rowland returns to Alaska at last and has to face down his haul road nemesis: chaining up. Meanwhile, failing trailer brakes and trash talk over the CB threaten to derail Lisa's comeback.

Jack, Hugh and Alex hit the haul road during a ruthless windstorm, with near-misses and disastrous engine trouble threatening to take them down. Meanwhile, Lisa, haunted by her recent missteps, sets out on the Dalton, determined to prove she is more than a pretty face.

Jack Jesse rushes to save the town of Nuiqsut with an emergency fuel delivery, but a blinding storm stops him on the thin ice of the frozen river road. Meanwhile, Lisa Kelly gets her big chance to step up when she's given her first oversized load. As she battles both the elements and the law, however, she begins to wonder if her trucking skills are up to the test.

As the temperature plunges, tempers flare after Hugh gets an earful from a driver who wants him off the Alaskan roads and back in Canada. Meanwhile, Alex takes a big risk by picking up a hitchhiker and Lisa struggles to get back on the road after a minor traffic safety setback.

When an avalanche strikes, Jack is left helpless as he watches the DOT clean up the carnage. Meanwhile, Ray faces the Dalton with a premonition of death hanging over him, and Hugh risks a head-on collision at 4,700 feet by driving on the wrong side of the road over Atigun Pass.

Lisa tackles the most dangerous haul of the season, trucking a multi-million dollar, 100-ton load across the entire state of Alaska. Meanwhile, Alex races to keep pace and Ray faces the worst night of his career when a spin-out at Ice Cut sends him over the edge.

Alex is thrust into a tough situation when a flipped truck leaves two men injured and one missing. Meanwhile, a careless mistake may rob Lisa of the hard-earned respect she has worked for all season long. Also, Greg fights for his job as Hugh devises a plan to steal a load from his old pal.

To reach the isolated town of Bettles, Jack Jesse must brave the arctic wilderness and cross a frozen river. Meanwhile, Greg takes on the biggest load of his career and Alex has a plan to one-up his rival Hugh. Will the Polar Bear go down without a fight?

A minor distraction sends rookie Ray Veilleux plowing into a snow bank and leaves him at the mercy of his fellow truckers. Meanwhile, trouble heats up for Lisa and Hugh when their cargo just won't stay put.

The Ice Road Truckers face one challenge after another when Ray spins out after pulling a risky maneuver, Alex ventures out onto the road with a burnt-out headlight and Greg experiences mechanical issues. Meanwhile, Jack lugs a 200-ton megahaul to Prudhoe and Lisa races to raise cash to buy back her horse.

The Ice Road Truckers take on a dangerous mission: the largest convoy the Dalton has ever seen on the road to Nuiqsut. On the way, they must navigate softening ice so that rising temperatures don't send them all to a watery grave.

A haul road legend's son heads to Atigun to say his final goodbyes and scatter his father's ashes but the legend's final ride puts Ray at risk. Meanwhile, Lisa's assigned to push-truck a monster load to Prudhoe, which leaves her feeling accomplished.

The Alaskan DOT races to stop potentially dangerous overflow from wiping out the Dalton and its truckers. Meanwhile, as the season nears its end, the truckers team up for safety, Hugh gets busted for speeding and Jack and Lisa come across an overturned rig.

Co-leaders Ray and Greg come face to face in Atigun, while Lisa's hard work pays off with an unforgettable reunion, Alex pushes to finally beat his nemesis and Jack's hope to repeat as King is in jeopardy in the season finale of Ice Road Truckers.