The Chronos Chronicles, Book 1: Time-Marked Warlock

Adair Finch is the most powerful warlock in the world, and one of the best private investigators for hire. He has dealt with corporate vampires, murderous werewolves, and even fae royalty. Everything was perfect until he lost one case — the case during which he also lost his brother. So Finch retired. From magic. From PI work. From everything. Bree Blackstone, a 12-year-old witch, doesn’t know or care about any of that, except Finch’s reputation. In the middle of the night, she bangs on Finch’s door. Her mother has been murdered, and now the assassin is after Bree as well. Reluctantly, Finch agrees to help, only to discover something sinister has been brewing in town while he ignored the world… To save his community, he’ll need to dust off all his old skills and magic before it’s too late.