The Wrong Familiar: Carnival of Mysteries - Megan Derr

Ninos has been training all his life to be a sylvan mage. Trees, plants, herbs, flowers, fruits, berries, nuts—he knows them all, and he intends to use that knowledge for the good of his home, a village he has not seen in more than a decade.

The final step to becoming a full-fledged mage is the conjuring and binding of a familiar, a faithful companion and guide who will supplement his power and remain at his side the rest of his life. Instead of a sylvan familiar, like a unicorn or stag, however, something goes horribly awry and Ninos finds himself bound instead to Sinn, a raven familiar meant for dark magics.

Neither is happy about it. Ninos wants a familiar who can help him with life, with growing and restoring a place destroyed by fire and plague. Sinn should be helping to raise the dead or cast blood workings. They were never meant to meet, let alone be bound.

Bindings are permanent, however, and cannot be broken. Their only chance at setting this wrong to rights is to locate the dark mage that Sinn was meant for, hope they in turn have Ninos' true familiar, and perform a rare but not impossible switch...