Toughest Deal by Alessa Thorn

The occult group Aurora is closing in on the Edgeworths, and they are going to need Altun, the Sorceress of Istanbul, to help them if they are going to stay alive.
Altun Baruk’s shady past with the Aurora and her vengeful sister, Dee, have finally caught up with her. She needs the Edgeworths muscle to back up her magic, and a damn good artefact to use as bait, if she’s going to have any chance of stopping Dee once and for all.
Julian Burbank is obsessive and curious by nature, and there’s something about Altun that he can’t get out of his head. Julian likes to be neutral when it comes to other people’s fights, but when Dee firebombs his office, all bets are off — and working closely with Altun again is a just delicious perk of the job. Julian loves a challenge, and he won’t stop until Dee is in the ground and Altun is in his bed.
Julian and Altun both know a good deal when they see it, but working together and fighting their growing feelings for each other will be the toughest one they ever make.