Marzia Bosoni 
World of Yesod — Earth [EPUB ebook] 

Continuing the story of Avir, Karka, Esh and Mayim who, having faced the dangers of the kingdom of Air, now find themselves crossing a dry and desolate country: the fertile and luxuriant kingdom of Earth is succumbing to the drought caused by the Enemy, which may even be waiting for the young Seekers right in the capital, Oldstone. From the unstable border hills to the caverns under the capital, and eventually reaching the distant Hills of Dorim, the friends continue their search for the legendary Key of Earth through dangers and puzzles, but also start bringing to light some truths about the history of the whole land of Yesod.