There's a couple of new protagonists here other than Shara. General Mulaghesh is sent to Voortyashtan to investigate the circumstances surrounding the death of a Ministry operative. Encountering mystery after mystery, she begins to realise that her mission transcends the murder of an operative, and that the fate of the whole world might be dependent on her very actions...
I felt that City of Blades was very much like City of Stairs: an operative on a covert mission to uncover a mystery, an even bigger discovery, triggering off a semi-apocalyptic chain of events... Point is, both books follow much the same lines of action.
While books 1 and 2 have more or less the same feel about them, City of Blades has a more...destructive feel to it.
Not too many surprises here, but a fine read nonetheless.