The animals of the north face worsening weather in autumn and the first stirrings of winter. Grey seals and reindeer turn their attention to mating, hormones run wild as males compete and young animals venture away from their parents for the first time. In Iceland, the cliff arctic fox family is thriving, but it’s a different story for the foxes denning at the shoreline. Only one of the cubs has survived, now abandoned by her parents, she must fend for herself. On the Monach Isles, 35,000 grey seals arrive for the annual breeding season. A pup faces danger on the beach, getting lost and swept up into a fight between two raging bulls. As winter arrives, the reindeer herd in Norway must migrate to their grazing grounds in the mountains but this involves a perilous two-mile swim across open water.

The lands of the north bloom as nearly 24 hours of daylight transform the snow-clad landscapes. Arctic fox clans struggle to raise their cubs on Iceland’s volcanic shores. On Shetland it’s time for the otter cub to strike out alone, while a lone puffin also searches out a partner. And in the mountains tiny reindeer calves take their first steps. As the season moves on, orca pods arrive in Shetland to hunt harbour seals, and fledgling seabirds take a leap of faith, plunging hundreds of metres from their cliff-top nesting ledges to the ocean below.

A single Arctic fox scurries across the mountains. He’s on a mission to reunite with his mate from last year, but has she survived the harsh Icelandic winter? All he can do is wait. In Shetland, a mother otter has successfully raised her twin cubs, one male, one female, to the brink of independence, but their journey will be far from easy - a dog otter is hanging around and determined to cause trouble. A huge March storm rages across all the Stormborn lands, disrupting the foxes' mating and reindeers' journey. But the otter family is the most keenly affected. Separated from the rest of her family, the female cub becomes isolated and afraid.