In the first episode, Helen seeks out the colours that turned planet Earth multicoloured. To investigate the essence of sunlight Helen travels to California to visit the largest solar telescope in the world. She discovers how the most vivid blue is formed from sulphur atoms deep within the Earth's crust and why the presence of red ochre is a key sign of life. In gold, she discovers why this most precious of metals shouldn't even exist on the surface of the planet and in white, Helen travels to one of the hottest places on Earth to explore the role salt and water played in shaping planet Earth.

The raw, early Earth had plenty of colour, but that was nothing compared with what was going to come next. That canvas was about to be painted with a vast new palette - and the source of those colours was life. Green is the colour of the natural world and yet it's the one colour that plants have evolved not to use. The huge diversity of human skin tones tells the story of how humanity spread and ultimately conquered the planet. But the true masters of colour turn out to be some of the smallest and most elusive. Helen Czerski travels to the Great Smokey Mountains of Tennessee during the one week in the year when fireflies light up the night sky with their colourful mating display. And she reveals the marine animals that hide from the world by changing the colour of their skin.

The colours that we see are only a fraction of what's out there. Beyond the rainbow there are colours invisible to our eyes. In this episode, Dr Helen Czerski tells the story of scientific discovery. To see the universe in a whole new light, Helen takes to the skies in a NASA jumbo jet equipped with a 17-tonne infrared telescope. We can't see in ultra violet, but many animals can. Helen explores what the world looks like to the birds and the bees. With the discovery of x-rays we could look inside ourselves in ways that previously had only been possible after death. Today those same x-rays allow us to examine life at the atomic level, helping to develop new drugs and better materials. Ultimately, by harnessing all the colours there are, researchers are beginning to image the human body as never before, revealing new ways to treat disease.