Riku is an angry, youthful warrior in ancient Disboard who is determined to save mankind from the warring Exceed, the sixteen sentient species battling to create the "One True God" among the Old Deus. In a lawless realm, humanity's lack of magic and frail bodies have made them easy prey for the other Exceed, putting the species on the verge of extinction. However, hope comes to humanity one day when Riku discovers a powerful female Ex-machina named Schwi in an abandoned elven city. Exiled from home Cluster owing to her studies on human emotions, Schwi believes that mankind has only survived because of the force of these emotions and is desperate to comprehend the human heart. forming an unusual alliance in the midst of the overwhelming chaos, Riku and Schwi must now find the answers to their individual shortcomings in each other, and discover for themselves what it truly means to be human as they fight for their lives together against all odds.