As fanciful as its predecessor but blessedly more cohesive, this quirky fantasy is a lovely ride. Three years have gone by; charming middle-aged sorceress Roberta Morgenstern is busy dancing with her boyfriend to call up spirits when random gory murders throw the city into chaos. Old-school detectives have been eliminated because crime is tracked by tracers, “[a]rachnids, aerial jellyfish, thinking dust-motes” with “fabulous memories” holding ample genetic information to identify citizens. But the trackers are inexplicably silent, so Roberta and her colleague Martineau snap into action. Meanwhile, a corrupt official whips the population into a frenzy persecuting gypsies in the Historic Quarter. Jubert’s spatial setup is so abstract that readers may never understand the lagoon, sunken buildings and city geography; a map is sorely needed. Marred only by the pretension of four identical footnotes urging you to read Book 1, this is a metaphysically creative and fantastical tale for fans of the offbeat. (Fantasy. YA)