Shizuka Kurokawa was a normal highschool girl, until she was summoned to another world with three other students. She and the other three were summoned to fight against the evil demon race, and of course they were given unique abilities to accomplish that. No, the other three did get their own abilities, but Shizuka got none.
Little did everyone know, she was already summoned as a hero before and still has the ability she got from that. She may not have any talent in magic and she might not have gotten an ability this time, but that's not really a problem when she has already reincarnated a hundred times, due to her heroic ability, and has gained a lot of bonuses from it.
