The prequel to The Maze Runner:
Earth has been devastated by catastrophic sun flares, and now a horrifying disease is spreading and mutating as it goes. Mark and Trina have survived so far, aiming to save their friends from the impending doom of the human race, but that's easier said than done. They'll do anything to stay alive and prevent the madness from consuming themselves and all those they hold dear...
James Dashner - The Kill Order