In this outing, Opal gets picked on some more. Pazia torments her in class and out, but she gets her own when she is recruited to thrown illusions at Opal to see if she can repeat her little trick of imprisoning them in glass and then being able to release them later to do her bidding. Pazia works Real Hard, and it costs her. Opal's ability to imprison souls in glass should have made people a lot more nervous than it did, but I suspect everyone was so busy being nervous about Yelena, and Opal cowered really convincingly, so no one really got it for a while.
Opal and a Master Magician go off to the coast to help the Stormdancer's whose glass containers for lightening are shattering in a lethal way. The old glassmaker died and the replacements can't seem to make orbs. Opal, with the assistance of her father, figure out how, but not why. After some more kidnapping, torture, and 3 different guys trying to get her in bed with varying degrees of success, Opal's got a lot better understanding of just how powerful she is.
In some ways, this feels like a mix-n-match of Tamora Pierce novels. There's the counterfeiting theme, complete with attempted overthrow of a ruler. There's the useful beggar motif. There's the glassmaking/unusual magic associated with Stuff. OTOH, YA has some genre constraints (I'm assuming this is YA -- maybe I'm wrong), so what do I know? Will I read more? Are you kidding? This stuff is disturbingly addictive. Don't say I didn't warn you.