Invisible Enemy, An

Two brave children battle environmental threats with the help of magic crystals and the guardians of the elements in a new climate fantasy series! Best friends Leah and Erik each have a leather necklace with a crystal on it. A crystal given to them many years ago by a mysterious woman. When the crystals suddenly begin to glow, they soon learn that they are filled with magical powers, and after that, nothing will ever be the same again... Together with the guardians of the elements, Erik and Leah embark on breathtaking adventures in four books full of excitement and magic. And they are prepared to do whatever it takes to save the world. In 'An Invisible Enemy', the first book in the series, Leah, Erik and the Guardians take on air pollution. But this is easier said than done, as people refuse to see that the environment is in danger. A plan takes shape, a plan as risky as it is ingenious - by taking some of the most influential deniers into the future and showing them the potential consequences of their actions, they hope to change their minds. Sera, the guardian of the air element, and Erik go with them, but the deniers are hard to convince. Leah and Erik find themselves years apart as the plan quickly fails and Erik is on the verge of taking his last breath...