Taking place 10 years before the beginning of Fate/stay night, Fate/Zero recounts the events surrounding the Fourth Holy Grail war in Fuyuki City. Originally begun by the Einzbern, Matou, and Tohsaka families, the Holy Grail War is a contest in which seven mages each summon a Holy Spirit, or Servant, to compete with each other to win the Holy Grail which will grant a wish to each member of the winning team. There have so far been three as yet inconclusive Holy Grail Wars, and now it’s time for round four.
Desperate to win, Einzbern enlists Kiritsugu Emiya - a mercenary hitman and Magus killer who will stop at nothing. However, Kiritsugu finds himself torn over the love he now feels for his wife Irisviel and their daughter Illya. Opposing him is troubled priest Kirei Kotomine who can only feel pleasure in other people’s pain but continues to fight against his dark side as he battles for the grail.