In the midst of the hunt for the Master Control Nanites, Rex discovers that Black Knight has been working on a secret project involving alternate universes. What has Black Knight found that warrants such a change in priorities, and what impact will it have on the war? The answer will decide the future of two worlds...

This story may contain spoilers regarding Generator Rex, up to and including the season 3 finale. A basic knowledge of the show helps, but the relevant points are explained for those who haven't seen it before.