In the fourth and final chapter of the series, Carol Klein takes a look at one of the most recognisable and influential flowers in our world, the waterlily. It is a plant of unlikely economic importance, spiritual significance and artistic inspiration.She travels to the far east to investigate when and where some of the first flowering plants evolved, and discovers waterlilies are among the earliest branches of angiosperms still around today - practically living fossils. Carol visits the Buddhist temples of South Korea and drinks lotus flower tea with the monks. They revere the lotus, a close relative of the waterlily. Later Carol takes part in a Korean festival held in honour of the lotus.Back in Europe, she meets one of the world's top experts in waterlily breeding and learns about of one of the most intimate known plant-insect relationships - a dramatic, overnight colour and sex change. Carol joins the waterlily and in its murky aquatic environment to uncover some of this iconic plant's ingenious adaptations, and its unique prehistoric pollinating system.