In the world of Plunderer, every person is born with a count that represents a certain aspect of their life. These counts can range from the number of kilometers a person has walked to the number of times they have said a certain word. The story follows a young girl named Hina who is searching for the legendary Ace, a hero who can save the world. Along the way, she meets Licht Bach, a mysterious man with a negative count who claims to be the Ace. Together, they embark on a journey to uncover the truth behind the counts and the secrets of their world.