Cast in Flame (Chronicles of Elantra)

Any day that starts with dragon arguments is going to be bad 

Kaylin returned from the West March in one piece. Now that piece is fraying. She's not at home in the Imperial Palace-and she never intends to be. All she wants is normal garden-variety criminals and a place of her own. Of course, normal in her new life involves a dragon as a roommate, but she can handle that. 

She can't as easily handle the new residents to the city she polices, because one of them is Nightshade's younger brother. On a night when she should be talking to landlords in perfectly normal buildings, she's called to the fief-by Teela. A small family disagreement has become a large, complicated problem: Castle Nightshade's latent magic is waking. 

And it's not the only thing.