City of Bones, the first book of The Mortal Instruments series, is based on an interesting premise however the overall book is essentially mediocre in plot and characters that are not well rounded.
Author Cassandra Clare envisioned a supernatural world hidden from the mundane world through various magical means, while an interesting twist on a well-used idea (not just by a certain author from Edinburgh), in execution it was a tad flawed. Her main characters, Clary Fray and Jace Wayland, are annoying for various reasons but mostly being illogical and a 24/7 jerk. While Clary finds herself going from normal teenager to learning her “hidden history”, she does some pretty stupid things that at time contradict previous actions and opinions she had just done or thought. Jace from the start is a major jerk, who never seems to change, even with the major revelations at the end of the book. Given their relationship development through the book, I wouldn’t equate it to Ron/Ginny it was more Luke/Leia and to be honest it’s hard to say who did the reveal better Clare or Lucas (if you can’t believe I just made that comparison I dare to you to watch Jedi again).
A lot of the “surprises” and “twists” in the plot were either plain to see, the reveal of who Clary’s real father is was pretty easy to guess and the character who turned out to be a werewolf was also easy to spot, while others were plainly botched and hard to read, the gay character reveal for instance. While the main antagonist was able to get away with the prized item that drove the plot it left the story the open ended to be continued, however the epilogue with Clary’s interactions with Jace, Alec, and Isabelle was cringe worthy in parts.
Overall, my opinion of City of Bones is simply, meh.