Timothy Martin is a respected lecturer in Astronomy who has spent most of his life trying to put behind him the trauma of a childhood dominated by 'visions'. But the visions have returned, more real than ever. Not only does see other places, but he is now able to step into them. When he becomes fixated on the star Delta Crucis in the Southern Cross constellation, he sees a vision of a world orbiting it and impulsively takes a step - two hundred and...