When one last battle against an unstoppable opponent with the shutdown of the game at stake, thirty years into the life of a VRMMORPG popular enough to hold the fate of the real world's economy in its hands, ends in failure, Alex finds himself returned to the day before release day, with 30 years to prepare for the coming battle.
Failure means the financial ruin of 5 billion players, but foreknowledge isn't necessarily a guarantee of success.