The latest (and certainly not the last) in Sheffield's far- future space-adventure series (Summertide, Divergence). Here, scholarly Darya Lang--just back from an encounter with the few remaining Zardalu (an especially horrid race of squid-like aliens that once ruled much of the galaxy) inside the Builder artifact called Serenity (one of many bits of mysterious super-tech left behind by a long-vanished race)--is swept up again into adventure by Hans Rebka and now ex-Councilor Julian Graves. It seems the Alliance Council will not believe their report of living Zardalu, and so, along with alien servants J'merlian and Kallik and the reluctant rogues Louis Nenda and Atvar H'sial, they set out after the Zardalu to get proof. The search leads into the dreaded Torvil Anfract, where physical laws are bent beyond recognition, and thence on to Genizee, where our heroes confront more Builder leavings (they litter the galaxy like old tin cans) and, of course, the fearsome Zardalu. Aside from the Builder wonders, there's little here for the mind but action-adventure bubble gum. Despite the vast passage of time, this future society is hardly changed from our present, and the plot (consisting mainly of inept chases by the Zardalu and comical exchanges between the characters) wears thin. Sheffield ought to have wound up this fading series with this book.