In a world torn asunder by the brutal machinations of war, a ruthless, atheistic corporate executive is reborn as a young orphan girl in an alternate reality reminiscent of early 20th-century Europe. This is the startling premise of this dark fantasy anime, which follows the precocious and calculating Tanya Degurechaff, a child soldier with the mind of a cynical salaryman. Driven by a fervent desire to climb the military ranks and escape the front lines, Tanya instead finds herself repeatedly thrust into the most dangerous battles of the Imperial Army's conflict. Her exceptional tactical genius and utter disregard for human life make her a terrifyingly effective weapon, yet her every success seems to draw the unwanted attention of a mysterious entity she believes to be God. As she rises through the ranks, Tanya must navigate the political intrigue of the General Staff and the horrors of the battlefield, all while wrestling with her own nihilistic worldview in a war that may have been orchestrated solely for her.