The far northern regions of Asia are dominated by long and bitter winters. To the south, in contrast, tropical Asia is dominated by continual heat and humidity.

Between these two extremes is a different world. Stretching from the foothills of the Himalaya in the west to the islands of Japan in the east are Asia’s temperate forests. Here plants and creatures have to find a way of living with both extremes, heat and cold, and adapt their lives to the four seasons.

The film focuses on a temperate deciduous forest in Northern Japan. In the warm, sunny days of spring we meet the principal character — the world’s northern-most monkey, the Japanese macaque. Also known as snow monkeys, these primates have adapted their travels with the changing seasons in order to survive. Just as the forest must move through the seasons, they must move through the forest in a constant search for food.

Yet while the monkeys must adapt to seasonal life, the trees have only two distinct stages — one for productivity and growth, the other for rest. And although the trees can cope with temperatures ranging from –20 degrees to +30 degrees celsius, their seeds need a prolonged period of bitter cold in order to germinate.

Other plants and animals also have to adapt to survive the extremes of the climates. In the shade on the forest floor is a plant, the Naniwazu. While all around the forest is delighting in the abundance of summer, the Naniwazu, starved of light, has shed its leaves and is in its "winter".

Other creatures of the forest have different ways of coping with the changes in temperatures, among them the big purple butterfly, with its life cycle cued to the warmer weather. It feeds on tree sap which is abundant in summer.

Then, as the seasons change, the forest starts preparing for the rigours of the winter ahead. The trees shut down, turning their foliage to reds and browns and yellows and the myriad of shades between.

The seasons are not a deterrent to survival for all the species of the forest, for everything is governed not by a clock but by determination and adaptation.