Nanatsu no Maken ga Shihai suru

Impressed by Nanao Hibiya's skill with a sword, Kimberly Magic Academy instructor Theodore McFarlane saves the samurai from certain death amid a fierce battle. With his encouragement, Nanao enrolls in the academy, where she instantly becomes a celebrity after she and four of her peers save a student from an enraged troll. Under the leadership of Oliver Horn, a young man who seems to hide a troubled past, Nanao and her newfound friends start their magical apprenticeship at Kimberly—where only four out of five students make it to graduation in one piece.

It does not take long for Oliver and his friends to experience the dangers of the academy firsthand, as a near-death encounter in the labyrinth under the school leaves Nanao grappling with her bloody past. The inexperienced yet determined students must stick together if they want to have a chance to survive and uncover the mysteries that the academy holds.