Enrolled in an esteemed all-girls knight academy, my brilliant younger sister outshines her peers. Despite her praise for my hidden strength, I see myself as unremarkable. A boast leads to a challenge from the school's top knight, revealing our true power gap. Through a chance act of kindness, I unknowingly garner attention, even from the princess. Surrounded by a harem of lady knights, I, an ordinary man unaware of my potential, find myself in an unexpected situation.