Trouble seems to follow Hideyoshino wherever she goes, earning her the label of an average girl. With an upcoming test to tackle, she visits a local shrine to pray. However, her plans for a peaceful moment are thrown off course when she spots a blue light emanating from inside the shrine. Curiosity getting the better of her, she investigates only to find a mysterious figure performing a spell. In a classic stroke of bad luck, Hideyoshino trips and crashes into the shrine, prompting the stranger to catch her. Unfortunately, their actions trigger an uncontrollable spell, sending Hideyoshino back in time to the Sengoku Era. Once there, she is greeted by Akechi Mitsuhide and Oda Nobunaga. However, things take a strange turn when Hideyoshino realizes that everyone in this era is female. She seizes the opportunity to help Oda Nobunaga find the Crimson Armor, rumored to bestow the wearer with the power to conquer all of Japan.