Mari Toujou, a university student, wakes up on a battlefield, bleeding from her neck. Without much time to comprehend the situation, she leads her team to a resounding victory and helps in capturing the enemy commander, Leon Midal. It is then that Mari realizes she has entered the body of Mary Flau Calkula, an oppressive queen who is despised by the people. Leon, who was once Mari's childhood crush, led a revolt against Mary due to her arrogant and extravagant ways.
Despite Leon being in their custody now, Mari can feel the same feelings she had for him before. She wants to demonstrate that she has transformed, but remnants of Mary's personality still clutch on to her. Together with Leon and the men in the palace, Mari hopes to build confidence in the monarchy and reconstruct her nation, while also perhaps discovering true love.
