The Gatespace Trilogy describes the experiences of several diverse groups of people as they encounter a mysterious, unexplained phenomenon known as the Gatespace, which manifests itself as "tears" in the fabric of space-time that show up as green, swirling "gates" that allow travel between locations in different points in both the when and the where.
 

PINBALL describes one man's discovery of one of these portals near his home and his compulsion to explore where it can take him, a group of researchers who discover how to open the Gates through means of technology, and the eventual abuse of this knowledge, which could literally cause the extinction of the entire human race.
 

REPLAY relates the story of Rick Harper, who is part of a research team that stumbles upon the secret of the Gates. When he is diagnosed with a life-threatening illness, he decides to attempt using the technology to influence his own past and try to add years to the time he has to spend with his beloved Stefanie -- with disastrous results.
 

Finally, in TILT, decades have passed since ChroNova's original discovery of the Gates, and the company's prohibition against using the technology for things like sightseeing have become all but ignored -- which may have the minor side effect of resulting in the mass extinction of all humanity.