Hypertime

"How does it work? Off the central timeline we just left. Events of importance often cause divergent “tributaries” to branch off the main timestream. But what’s astounding is there’s far more to it than that. On occasion, these tributaries return—sometimes feeding back into the central timeline, other times overlapping it briefly before charting an entirely new course. An old friend is suddenly recalled after years of being forgotten. A scrap of history becomes misremembered, even reinvented in the common wisdom.

There are hazards to Hypertime, of course.... Artifacts carried into differing hypertimelines dangerously break down the barriers between kingdoms...but you’ll learn more about that in the months and years to come."

http://www.hyperborea.org/flash/hypertime.html