Deep in the Mongolian taiga Colin Monteath travels with nomadic reindeer herders during their spring round-up. The Tasaatan people release their reindeer above wolf territory to feed safely on lichen during the winter. When the season turns the herders must round up their charges over a daunting landscape the size of Switzerland. Their domesticated reindeer are thrilled to see them - not only do the animals crave human company but after a winter in the snow they are salt-starved. Knowing that the herders bring bags of salt with them the reindeer happily follow them down to the lowlands to spend the spring and summer.