Donal traces the arrival of summer from the extremes of heat in the desert to the idea of a perfect summer in the temperate climates of the north. He visits the jungles of the Belize where the sunâ€™s energy is most intense and where the weather is both wet and hot. Fortunately this weather is rare but in 1995 Chicago experienced a heat wave which killed 165 people. Heading for the desert he attempts The Marathon des Sables an exhausting and dangerous seven-day test of ability to see what effect dry heat has on the weather, from mirages to the deadly desert sandstorm that is the haboob. Finally Donal explores the energy behind lightening before getting first hand experience of being struck by it.