The Valkyrie Chronicles

When a weakness of Valkyrie sight is uncovered, Kara, Kate and an unlikely ally, must race against time to stop a saboteur before Valhalla falls. Arina copes with being a new type of Valkyrie and defies Odin while reminding the ruling caste what the ideals of the Asgard are and what they should all aspire to be. She must help a young Ragnarok, who was sent to die at the gates of Valhalla, to learn the truth about the Asgard and her own people. Old enemies and lost friends weave a web that could spell the end for one of Odin's own.