Wasteland Blues

Sometime in the not-so-distant future, all water on Earth is infected by an unknown bacteria, resulting in an epidemic that kills more than half of the population. As the planet is already dying, the rich and influential take this opportunity to abscond to a manmade planet, Ceres, which can only sustain a small amount of people. As a result, children aged 13-18 are left on Earth to compete for top ranks in institutions known as Schools, out of which only the top five per age group will get to leave Earth.
Sasha Reid is a boy travelling across London with an illegally-obtained ticket off Earth, but something goes wrong and his life is saved by a girl who seems to have her life on this planet all worked out. However, when a plot against her forces them both to go on the run, they have no choice but to turn to a secret (and illegal) gladiatorial club where the last one standing will get a ticket off Earth.
But there can only be one winner.