City of Ashes

Clary is a girl with unusual friends. Luke, for example, is a werewolf. Jace, her brother, is going to be tried by an Inquisitor. Valentine, their father, is an incredibly evil individual. Simon is her boyfriend, at least until he gets turned into a vampire. There are also an assortment of demonic beings and sort-of evil fairies that she has to deal with.

There's also a physical attraction between Clary and Jace, complicating matters quite a bit. One rather humorous incident is when a demon attacks Clary, takes a good luck at her, and promptly runs away!

The Inquisitor has her own agenda; she plans to trade Jace to Valentine for some special weapons Valentine has.

Then things erupt into the beginning of a war. Valentine has summoned numerous demons of various types, and what Shadowhunters are available arrive to battle them. What was dead is shown not to be quite so dead. Shadowhunters are killed, and demons destroyed and, as expected, the big guy gets away, setting us up for a third volume.

This is a really, really good second book in the series.