Engineer Janet Thompson steps through a doorport to San Diego, but lands in San Francisco instead. The worldwide doorport network has operated without a glitch for forty years. What could possibly be going wrong?
The lives of six people are changing in dramatic ways, each of them having little awareness of the changes. As Janet tries to revamp the forty-year-old doorport system, she realizes that years of use have begun to have an effect on our world. While she investigates the occurrence, permutations in space-time become more apparent, more numerous, and more pervasive than she could have ever imagined. How can she save the fabric of space-time from complete collapse?