I am enjoying the arc of Kay's realizing first that Lucy is perhaps not just a sociopath, but also may be a dangerous sociopath; and Kay's exploration of how badly she spoiled Lucy and indulged Lucy's narcissism.
Kay has avoided fully acknowledging these glaring dangers with the belief that Lucy is, when it comes to her loved ones, a weapon pointing outwards from their wagon circle. But now, Kay is facing the fact that isn't true.
She has also avoided facing head-on the fact that Lucy's ravens have and will come to roost. Every selfish, dangerous thing she has done, every emotionally or physically violent act, every careless relationship...and every time Kay has fixed it all for her (special treatment in the Quantico dorms, for example)... consequences are and have been coming due all along.
coming this autumn: no. 24, Chaos