While driving through Kansas a very ordinary man named John Christian encounters an extraordinary being called "The Keeper". He tells John that an age-old conflict between the inhabitants in his world is about to result in unthinkable death and destruction. This strange being believes that John can help prevent this tragedy. John is taken to the Keeper's world, where he meets Kate Fleur and Simon Platt. The Keeper has brought them there as well.

One group of the inhabitants has built a magnificent wall to keep their enemy out. John observes that the wall has been equally effective in confining its builders. The prejudices of the beings in the Keeper's world are familiar to the three strangers. And the politics practiced there mimics the all too familiar political chicanery in this world.

Kate gives the people new hope for life. Simon exposes the cruelty of their traditions. John overcomes his self-doubt and discovers that he has the ability to lead. But the inhabitants of this world must ultimately make the decision to opt for peace themselves. Fortunately the hope for a better life can be found in the hearts of the inhabitants of that world, as well as our own.