Spark by Mitch Johnson
Ash has always lived in Last Village, lonely since the day his father left and never came back. The world is unbearably hot, water is drying up, and life is hard.
After a vicious thunderstorm, Ash wakes to find that the village's water has completely run out, and all the other villagers have mysteriously disappeared. Accompanied by the outcast Bronwyn, Ash sets off in search of water, for answers about what happened to the villagers, with hope they might find 'The Kingdom' - a rumoured land to the north where life still flourishes. Ash and Bronwyn have to survive a journey across an arid landscape, discovering that other people out there are even more dangerous than the lightning strikes that follow them.
Then they reach The Wall - beyond it, something impossible. Lying in wait are the answers Ash is searching for, and maybe even the truth about what happened to his father. If only he could get past The Wall...
Sometimes all it takes is just one spark.