3.5 stars. So much to love in Shadowshaper, but I found myself frustrated as well. First of all, I love Sierra. I love her attitude, her characterization, her voice. I love her cool cobfidence as well as her very realistic occasional insecurity during private moments. I love that she rightfully calls out Robbie, who disappears so frequently that sometimes it felt that he was as much a shadow as the actual spirits. I love the dialogue (which I could hear perfectly, as if someone were reading it to me or I was watching a movie) and the vivid setting and the gorgeous mythology of the shadowshapers. I love Sierra's friends and their loyalty. 
 What I did not care for, however, were the action sequences. Unfortunately, because Shadowshaper is quite a short book, there are a lot of action scenes squished together often. The best word I could use here is chaotic. I've said this recently about another book, but the writing during the action-packed moments is best equated to shaky cam cinematography, and that is not a style that works for me, in film or on the page. I found those scenes to be unfocused and.... blurry? Maybe? The pov is third person limited (Sierra) so I understand we, the readers, are not as distant from the action, and perhaps the shaky-cam quality is intended to keep the reader in the moment, but so often I found myself so into the scene that I would have read three paragraphs without absorbing anything and having to go back and reread more carefully. That's probably also on me as the reader, but I found it frustrating. I read 60 pages of Shadowshaper right off the bat, but after several of these occasions, I found myself avoiding picking it back up (despite the fact that I LOVE the premise and the characters), and that's something that makes me knock off a few stars. 
 Overall, really interesting story. It's not entirely unique (the comparison to TMI is apt), BUT the culture and mythology of the shadowshapers and the characters' interest in their ancestors took the story in a very cool and personal direction. Give this one a try.