Tatsumi is summoned to a new battlefield, this time as the Berserker of Red in a grand Holy Grail War. The prize? A wish-granting chalice that could rewrite the past and undo the tragedies that took place all those years ago. What a chance to rewrite his fate. Tatsumi faces the ultimate choice: to continue fighting for the future or risk everything for the chance to redo it all. But why does he feel as if this is all for the amusement of a vampire troll?