The JLA is used to dealing with threats from outer space, but the one they’re faced with in this case isn’t something they can fight head-on. It’s a virus of some kind, spreading from a meteor that struck near a small village in Africa, incredibly virulent, and with no apparent cause or cure. The JLA has to contain the threat, quarantine the area, search for a cure, and deal with the panic and unrest the news of the virus causes, plus the resentment and fear caused by their very attempts to help. All at once. Such a task would strain the resources of any roster, but fortunately the JLA has some of the most powerful and well-respected members the world has ever seen.