Jarek Reen is trying to save a lost world. He discovered the primitive theocracy of Serenein by accident, and now he wants it to take its place in human-space. To do this he needs a shiftspace beacon - without it, there is no way to find the planet again. The beacons were made by the Sidhe, the race that originally gave humanity access to the stars - and dominated human-space for millennia, before a coalition of human rebels and Sidhe males brought the evil Sidhe females down.

Most people think the Sidhe are long dead, but Jarek knows better: a renegade female Sidhe is one of his companions, and a male Sidhe gave her and her lover the special powers that made them Angels, very unusual trained assassins.

Jarek's only hope is to find Aleph, the hidden system where the last Sidhe males are rumoured to live. But even if he can persuade these eccentric, introspective beings to put aside their interminable internal squabbles, he still has to persuade Serenein that joining the rest of humankind is a good thing ... for the price of progress is likely to be high. Can he stop it turning into tragedy?