Hello, Darkness. Mathilda Holiday, #3

Who can you trust when your allies' minds are no longer their own?Mattie and Tillie finally seemed to be gaining ground against the Auditors - the shadowy secret society of mages that has hunted them for months. With the help of former Auditor agents who defected to their side, victory felt possible. Until those same allies begin turning on them. Whatever spell is controlling the former agents isn't anything they recognize - and it may be stronger than anything the Auditors have used before.
If Mattie, Tillie, and Trevor can't uncover the source of the magic and break it in time, they won't just lose their progress against the organization. They'll lose their friends. Hello, Darkness is the third book in the Mathilda Holiday series - a fast-paced urban fantasy of secret societies, dangerous magic, and the cost of fighting back.