The Marronnier Kingdom is a prosperous landlocked nation surrounded by seven other countries. Twenty years before the story begins, the continent was shaken by a great war that left the Marronnier Kingdom at its center, and lingering tensions still exist between the neighboring states. Aware of the fragile political situation, the kingdom's Prime Minister decides to send a knight on a diplomatic mission to each of the seven surrounding nations to maintain peace and demonstrate goodwill. The chosen envoys are the seven sons of the famous and formidable General Baribara.

The seven brothers are the story’s central protagonists, each a knight with a distinct personality and a unique trait that defines him. Among them are Nemukunai, who cannot sleep, and Harapeko, who is eternally hungry. Their mother, General Baribara, is a powerful figure whose own origins lie outside the Marronnier Kingdom, a fact that raises questions and suspicions both within the court and in foreign lands about her true intentions and the nature of her children's power. The brothers are sent to the seven different kingdoms that surround their home, tasked with serving as ambassadors to foster friendly relations.

Each brother’s journey becomes its own narrative arc, with the story exploring a different neighboring country and its unique culture through their eyes. These arcs blend political intrigue with slice-of-life moments, and also incorporate adventure, romance, and action. In one notable arc, a brother codenamed Tamer or Dompteur is dispatched to the Land of Beasts. His mission is to find a missing Marronnier diplomat named Saturno. To aid in his search, he is joined by a mysterious young woman named Xilonen who has been transformed into a bird, but the mission proves to be far more dangerous than it initially seems. As the seven knights travel to nations with vastly different customs, fashions, and landscapes, a deeper mystery unfolds surrounding their family's connection to the political machinations that link all the kingdoms together.