City of Bones has an intimidating ring to do it, doesn't it? It has an allure, too, like the Elephant Graveyard in The Lion King, which is a city of bones Serengeti-style for Simba. However, the haunting Silent City under the New York Marble Cemetery turns out to be a place to uncover secrets, not to bury them.
But let's back up a bit. This is the first book in Cassandra Clare's Mortal Instruments series. In City of Bones, the Mortal Instruments are a series of magical relics (think Deathly Hallows) that the forces of good and evil are scrambling to recover. Sound straightforward? Well, think a little harder, and you might wonder if there's a larger power behind the scenes pulling the strings.
At this point, we have no idea what's going on behind the scenes, but it's always possible, whether it's God, the devil, or something else entirely. Clary and her friends won't live forever (i.e. they're mortal), and what if someone is playing them all like fiddles? Clary's crew could be mortal instruments themselves, pawns in a larger game.