The Lereni Trade — Melanie Nilles

She grew up disregarded by all and put her attention into studying, but Krissa longed for friends. In her lonely life, an alien abduction was the last place she expected to find them. But it's not by chance that they've found her. Her Lereni captors have plans for her as an exchange to save their world from its ruthless conquerors, the Tah'Na. Only her life can free them, but not even they know why she is worth the freedom of a whole planet. A possible clue rests on her wrist, a stone bearing a symbol from another alien race. One Lereni will show her what friendship means and defy his commander to save her, but they may all need angelic intervention.