Vengeance of the Demon: Demon Novels, Book Seven

Demon summoner Kara Gillian is on the wrong side of the law-and there's evidence to prove it. Too bad the courts don't accept "fighting demonic forces" as justification for murder and mayhem. Yet Kara has problems that go way beyond her legal woes. When the enemy demonic lords spur their human accomplices into high gear, master summoner Katashi aggressively pursues their goal to establish a permanent gate between Earth and the demon realm. To hell with the consequences for humanity. The line between ally and enemy blurs as Kara gathers the remnants of her posse to prevent a devastating demonic incursion, but a shattered trust may cost them the war and put Kara behind bars. With treachery rife, and her loved ones in danger, Kara must call upon the essence of who she truly is in order to rally back from a crushing loss. And if she can't, the world is going straight to hell.