What was going to be an ordinary study abroad program in France for Robin Fea, with a looming Holy Grail War, soon turned hectic as not only was she chosen to be a Master by the grail, but her best friend, Bryn. Robin summons her servant, an Avenger, who completely contradicts her gentle motherly demeanor and love for pastel aesthetics and making people happy. How did someone so mediocre as she summon an Extra class servant? What does this mean for the war, let alone herself? How will she and her servant get along with one another as polar opposites?