Jack is little Reggie's imaginary friend. He might also be the holographic assistant to a ship's master who is about to take her vessel on the first jump to the Kepler system, and the familiar spirit of a young man who awaits execution for witchcraft in one of Lancaster Castle's dank cells. By one name or another, he inhabits the world's history, from alpha to omega. A Roman boy-emperor dances for him, a modern-day diva sings for him and a young catholic priest feels the touch of his wings. Always in the shadows or in peripheral vision, Jack links stories that span a period from 3rd Century Imperial Rome to several hundred years into the future, and subtly changes many lives, from a stiff and starchy 1930's RAF pilot, to a transgender girl living in modern Italy.