Returning with Valkyrie, Kazuto, Akina, Hydra, and their companions, they encounter the sudden appearance of the Key of Time and various enigmatic events. These occurrences all point towards Valkyrie Ghost, whose singular ambition is to claim Kazuto as her own. United in their struggle against this formidable adversary, they delve into the enigmatic history of Valkyrie's native world, Valhalla.