Fan CastingThe Homecoming Saga by Orson Scott Card

In a distant future, mankind has forgotten its self-destructive Earth origins. Put in place to ensure that it does not destroy itself again is an omniscient computer, linked in a genetically hereditary way to all humans on the planet. But as centuries pass the genetic link weakens. People are able to conceive of the forbidden things, such as weapons for more than hunting, or flying machines, or world domination. One genius crippled boy begins investigating these oddities and discovers that his younger brother, too, is having visions of the distant past and humanity’s renewed potential to endanger itself. Meanwhile, their older brothers become embedded in the new regime. Are two young men, and two young orphaned girls with oracular powers, enough to stop a new planetary crisis?