The eldest son, Nemukunai, readily accepts his engagement to Eleonora, the castle lord's daughter. Behind the scenes, various motives intertwine. Within the castle, a sword-fighting tournament is held among the knights, with the sixth son, Kenjiman, and Eleonora, Nemukunai's fiancée, advancing to the semi-finals. A fierce battle unfolds as the brothers watch, neither giving an inch. Eleonora then learns that she has been chosen as the assistant knight commander to accompany Nemukunai on his journey to the "Land of Long Nights." Is it political maneuvering, fate, or something else…?

The fourth son, who is always cold, is unaware of her true identity and finds himself drawn to Princess Brunhilde, who is disguised as a man. However, when he learns of a series of inexplicable events surrounding her, he begins to suspect that someone is interfering. As he sets out to uncover the truth, something strange begins to happen to him as well. Meanwhile, the eldest son, who is not sleepy, is chosen as the first "ambassador" to be dispatched to various countries. And his fiancée is about to be decided. And who is she...?

The Kingdom of Marronnier lies in the center of a continent comprised of eight nations. In this kingdom, the female general Baribara, who commands the knights, has seven sons, each with their own unique personality. "Never sleepy," "Philanthropic," "Easily gets hot," "Easily gets cold," "Animal tamer," "Swordsman," "Always hungry"—each possessing different qualities, they share only one common goal: "To one day heroically rescue a princess!!" The brothers embark on a journey as "ambassadors" to the seven nations, searching for their destined partners. A story of love and adventure begins!