Alcia is a world governed by Count: numbers engraved on a person's body, representing any number related to their life. These Counts determine a person's social status and power in Alcia. If a Count reaches zero, the person is sent to the Abyss, a place rumored to be worse than death. Hina, a traveler whose Count is based on the distance she traveled, witnessed her mother get dragged down into the Abyss. Determined to fulfill her mother's last wishes, she sets off on a journey in search of the legendary Aces—heroes of the war that happened three hundred years ago, bearing a white star next to their Count. While wandering around, Hina encounters Licht Bach, a mysterious masked man with negative Count, and Nana, the owner of a tavern. In the midst of having a good time, Hina is tricked into a battle with a military soldier. However, despite his negative count, Licht rescues Hina and reveals that he has another count, one with a white star, one of a legendary Ace. Plunderer follows the journey of Hina and other inhabitants of Alcia as they discover the truth about their world, the Abyss, and the legendary Aces.

After a curse turned him into a pig, World War I ace Marco Pagot becomes Porco Rosso, a mysterious bounty hunter who takes down sky pirates in the Adriatic Sea. He whiles away his days on a secluded island, rarely leaving other than to collect bounties or to visit the beautiful Gina, a songstress and owner of the Hotel Adriano. One day, while traveling to fix his faulty engine, Porco Rosso is gunned down by a young American hotshot named Donald Curtis. Thrilled at the possibility of fame, Donald boldly declares that the flying pig is dead. Not wanting to disappoint Gina, Porco Rosso flees to the famous Piccolo S.P.A. airplane company and takes out a massive loan in order to repair and improve his fighter plane. There, he is surprised to find that the chief engineer of Piccolo S.P.A. is the 17-year-old Fio Piccolo, who hungers for a chance to prove herself. With Fio's improvements, Porco Rosso prepares to challenge Donald officially and regain his honor.

Due to the incredible success of the Sibyl System, Japan has begun exporting the technology to other countries with the hope that it will one day be used all around the world. In order to test its effectiveness in a foreign location, the war-torn state of the South East Asian Union (SEAUn) decides to implement the system, hoping to bring peace and stability to the town of Shambala Float and keep the population in check. However, a group of anti-Sibyl terrorists arrive in Japan, and the Ministry of Welfare's Public Safety Bureau discovers significant evidence that the invaders are being aided by Shinya Kougami, a former Enforcer who went rogue. Because of their past relationship, Akane Tsunemori is sent to SEAUn to bring him back, but with their last meeting years in the past, their reunion might not go quite as planned.

Three years ago, the long war between the Royal Empire and the Republic of Frost came to an end. With both nations a long way from recovery, a passionate young woman named Alice L. Malvin leads the Pumpkin Scissors, a unit of the imperial army specializing in war relief. During a mission to assist a village occupied by renegade soldiers, Alice meets Randal Oland, a scarred former soldier with a sordid past and kind heart. Encouraged by the efforts of the Pumpkin Scissors, he joins the team on their mission. During the assault, however, Randal enters a trance-like state prompted by a mysterious blue lantern. As a result, he acquires monstrous strength and decimates the enemy forces. Despite having witnessed Randal's disturbing transformation, Alice invites him to join her squandrant, confident that his gentle nature will prevail and make him a perfect fit for the Pumpkin Scissors.