It's easy to describe Sarah Gailey's Magic for Liars as "Harry Potter meets noir murder mystery", at least in the beginning. Most of the action does take place in Osthorne, a high school for young mages (NOT witches or wizards!), and the protagonist, Ivy Gamble, has been asked to solve the mystery of a gruesome and inexplicable death that took place on its hallowed grounds. This case offers a significant professional and financial upgrade for Ivy. However, it is complicated by the fact that Ivy's estranged twin sister Tabitha is a mage and a teacher at Osthorne.
Ivy's familiarity with magic gives her an advantage that most other private investigators would lack at Osthorne, which is why she was hired. Unfortunately for Ivy, her familiarity is second-hand through Tabitha, as she is not magical at all. She resents Tabitha for her advantages and feels that she is muddling her way through life.
Ivy's self-pity permeates the first third or so of the novel. She sees Osthorne as an entree to a life that she might have had. Even students using their magic in ways that teenagers would, such as permanently writing that another student is a "slut" on a set of lockers, irritates her. She thinks of this as a waste. But when the action picks up and Ivy meets some interesting leads, the tone picks up a bit, too.
Ultimately, Magic for Liars is much more about a woman making peace with her past, her family, and herself than it is about either magic or a mystery. That said, both the magical world of Osthorne and the mystery are fairly engaging, too. Secrets are revealed about several members of the Osthorne community and about Ivy herself. I will note that many characters are LGBT, which appealed to me, especially the casual way that Gailey described their orientations. This won't be a novel for everyone, but if you enjoy genre fiction, you could find much worse ways to spend your time.