Nica of the New Yorks — Sue Perry

Now that Nica has a taste for life in the Frames - the endless multiple dimensions so bogglingly like yet unlike our own - she can't wait to get back to work with the allies in the fight against Maelstrom. Being Nica, she applies her detective skills to solve problems she hasn't been asked or permitted to tackle. Meanwhile, the universe prepares for war. In the New Yorks are Frames of such power that the land imparts strange partial sentience to all, and Nica's roster of allies includes old pals and recent comrades plus local beings, landforms, and structures, notably a self-help book, a river, and a street musician with an unfathomably dark past.

This is book # 2 in the FRAMES quartet.