Catherine Fisher is one of those authors who, even if a story isn't the best, still creates a unique, hauntingly vivid world. "The Dark City" is a pretty good example of what she can do -- she crafts a grim, rainy sci-fi/fantasy story with a startling twist, set on a world that is slowly dissolving into darkness. 
 Long ago, the powerful Makers made the world, except for the Sekoi (who existed before that). Their powerful relics are still strewn around, and the Order of keepers has devoted itself to finding those relics and keeping them safe. Unfortunately, the evil totalitarian Watch has almost wiped out the Order. 
 Raffi and his master Galen have been living in hiding for years, only coming out to find relics. But then a small-time warlord steals a relic from them, and declares that he will only give it back if Raffi and Galen bring back a Sekoi storyteller from the cursed dark city of Tasceron. 
 Galen is fine with this, especially when they learn that the legendary Crow is in Tasceron. Since his powers have been crippled, he hopes the Crow can restore it. However, the two keepers have no idea that their travel companion Carys is a secret spy for the Watch -- and that the Dark City holds shocking secrets about their world's past. 
 The world of "The Dark City" is a pretty grim one -- Fisher crafts a gritty, rainy world, which has decayed into a sort of totalitarian Dark Ages. And while I won't mention what the twist involving this world is, Fisher carefully weaves in countless hints about the Makers, their relics, the Sekoi and the nature of this world. 
 The biggest problem is the magical powers shown by Galen and Raffi. Given what is revealed about their world, I'm not sure what these powers are or where they come from. 
 However, Fisher's writing is in top form here. Her prose is richly evocative, filling her story with mud, rain, misty green seas and nightmarish cities clouded with darkness. And while most of the story is devoted to the journey to find the Crow, the story still feels lean and uncluttered with filler or side-stories. 
 It also has a fairly interesting trio of characters -- there is Galen, a man obsessed by the loss of his powers, and desperate to somehow regain them. Carys is a rather cold-blooded spy, but one who slowly discovers the truth about the Watch as she travels. Raffi is the weakest of the three characters; he's just sort of THERE, trailing after Galen like a wet puppy. 
 "The Dark City" is a richly-imagined, cleverly-written sci-fantasy story, and the big "to be continued" ending promises that there will be more.