The Song Between Worlds

Aelik is trapped policing fae activity on Earth, while also a spy within the human military division hunting proof of fae. Both jobs are far too respectable for comfort, with no path to freedom on offer. While Earth is a nice enough place to visit, the natives smell.
The situation worsens when he hears odd sounds around the stone circles, and frequent reports of shadowy creatures visiting Earth forces him to work with other Border Guards.
Increasingly entangled by the intrigues on both Earth and Faerie, he might be forced to actually make a choice. And running away isn't one of the options.

Book 2 of The Border Guards trilogy.