Neverthorn Academy by Shannon Mayer

Harlow is a 29-year-old wizarding school dropout who is blackmailed into returning to Neverthorn Academy to help defend against the dark wizard Nocta.

So now she's stuck retaking all the classes she didn't pass the first time and being mentored by the annoyingly sexy Professor Typhon.

But Typhon and the other professors are hiding a secret and Harlow needs to figure out what it is and fast.

Because Nocta is coming for Neverthorn and Harlow might be the only one who can stop him.

Otherwise the world as she knows it will be destroyed forever

ISBN: 9780241701843