UFO Ultramaiden Valkyrie 2: December Nocturne

Valkyrie, Kazuto, Akina, and their friends return for another adventure in UFO Ultramaiden Valkyrie 2: December Nocturne, which centers around the sudden appearance of the Key of Time and various other unexplained events. The Key of Time seems to be connected to a person known as the Valkyrie Ghost, who is determined to kidnap Kazuto. In their efforts to stop the Valkyrie Ghost, they uncover more about Valhalla's mysterious past.