This book was amusingly tiny. Not thin, but the actual book is smaller than books typically are. It's cute.
Fern's School for Wayward Fae is a school in the nowhere realm, which is between all the other realms. Demifae are taken there by Fern, a mysterious redhead. The students remain at the school until they turn sixteen, which is when they must pick a realm to live in. There's Earth, where several of the students are from, and Faerie, with its warring factions of Seelie vs. Unseelie. There are also a ton of other realms, but those are the main ones.
Rosemary has the unwanted gift of being able to see when/how people die. She doesn't know the exact when, but if the person is a lot older, obviously it's going to be in the long off future. Naturally, she creeps people out, including her mother, who ends up sending her off to an institution. Thankfully, Fern gets her out of there and she's handed off to her new mentor, Dante.
There's a whirlwind of getting to know the school and its handful of inhabitants. Some are Seelie, so imagine the fairy tale-type fairies. The nice ones. Some are Unseelie, like Rosemary's new roommate. Trym is a banshee, who screams every night at 3:33am, so her roommates all have to wear enchanted earplugs or...die. One of the Unseelie is half-vampire, another half-ghost. (No, they don't explain the logistics, but at least Rosemary briefly wonders how that works.) Another is something that can travel through shadows.
Rosemary becomes closest to Essie, who's a djinn and learning his wish-granting powers. When he goes missing, she's determined the adults aren't telling them the truth, so she, Trym and two other students are off to the rescue, which involves a lot of realm-hopping in search of the passage to Earth.
I really enjoyed this. I like all the different abilities and the faerie politics. It ended on quite the cliffhanger, too. It's a quick read, but not too quick. I'd say it's middle grade, but definitely also adult-friendly.