Once every thousand years, the gods of various mythologies - including Greek, Norse, and Hindu - come together to deliberate humanity's fate. In light of our species' conceit, the council is united in their decision to eradicate all of humankind. However, Brunhilde - one of the thirteen Valkyries who dwell in Valhalla - intervenes during the meeting to offer our kind one final chance at survival. Brunhilde's counterproposal involves a competition known as Ragnarök, in which the thirteen most formidable individuals on Earth would each face a god one-on-one. While the gods initially scoff at this suggestion, Brunhilde shrewdly manipulates their overconfidence into acquiring their approval. Now, she must scour human history to find the greatest heroes who have ever lived and guide them to victory before their inevitable demise.