Rhys Blackshear is surely his father's son: they share many of the same gifts, and Rhys not only resembles him strongly, but has his physical strength and intellectual prowess. At fifteen, he's insatiably curious and more than anything wants to find a way to bring the simulated citizens of Saint Francis out into the real world—a desire that counters laws forbidding advanced artificial intelligence.
Hyrum, his uncle and best friend, just wants Rhys to be happy. On a mopey day, he convinces Rhys to go outside to have an adventure—eating all the foods they shouldn't and riding Hyrum's treasured red bicycle with shiny new passenger pegs—when a mishap sends them out of control down a major hill at high speed, and lands them in a completely different When, inexplicably in a new location.
It's there they meet a much younger Aisha and Emperor—Rhys's future parents—and discover that not only are they not at all close to reconciling, she's so angry with the Emperor that he may never have a chance to close the distance between them…and if that never happens, Rhys won't be born in this When, nor any other future When.
Rhys has no idea how he, Hyrum, and Wick landed in Las Vegas, and he doesn't know how to bridge the gap between disparate Whens. He especially has no idea how to convince Aisha to forgive the Emperor, nor how to help him fight for the woman he loves.
His new want: to be born again, to become one of the recycled souls that greet each new When, and despite all of time to play with, he has no idea how to get home, nor how to fix any of it.