A wild light - Marjorie M. Liu

Maxine finds herself covered in blood and crouched beside Jack's dead body, with no memory of what happened. Grief-stricken, Maxine isn't sure what to believe - or who to blame.

Then an Avatar bounty hunter comes through the veil into our world, investigating a death of his own. Completely ruthless and subservient to those who bred him, his mission is to find Jack - dead or alive. Racing to stop the hunter, Maxine must also deal with the blood on her hands. But the answers she uncovers will be devastating, and the earth's salvation won't wait.