In the northeastern reaches of the Dunan region lies the powerful military nation known as the Highland Kingdom. Two young boys, Riliu and his best friend Jowy, serve together as members of the Unicorn Youth Brigade, a military youth corps of their homeland. They share dreams of a peaceful future, looking up at the same starry skies and believing that once the fighting ends, their daily lives will return to normal. However, contrary to their hopes, the two become swept up in the whirlpool of fate as the flames of war engulf the region. As conflict erupts across Dunan, the powerless boys reach for and grasp immense power, stepping forward with their own beliefs in response to an answer-less question.

The narrative follows Riliu, a kind and protective young man raised in the town of Kyaro, and Jowy, his intelligent and determined best friend who comes from a noble family. Nanami, Riliu's cheerful and energetic stepsister, cares for their home while the boys serve in the brigade. As the story unfolds, the legendary 108 Stars of Destiny begin to gather, shining brightly in the murky horizon. Riliu and Jowy find their friendship tested as they are guided by the flames of war toward an uncertain destiny. Along their journey, they encounter a cast of memorable allies including the wandering mercenary known as Viktor the Vagabond and the skilled swordsman Flik, called the Blue Lightning, who accompany them through the growing conflict.

The anime adaptation draws directly from the storyline of Suikoden II, the second entry in the classic role-playing game franchise originally released in 1998. The series expands the source material's themes of friendship, betrayal, and the heavy costs of war into a full narrative arc. Key antagonists include Luca Blight, the crazed prince of the Highland Kingdom known as the Mad Prince, whose cruelty drives much of the conflict. Opposing him stands his sister Princess Jillia Blight, who rejects her brother's brutality. Other notable characters include Rowd, an ambitious captain of the Unicorn Youth Brigade; the young girl Pilika from Toto village who forms a close bond with Jowy; the magic expert Luc, apprentice to the guardian of destiny; Shu, a brilliant strategist expelled from the Mathiu Silverberg strategy school; and Apple, a young strategist and Shu's fellow student. The series also features Mukumuku, a flying squirrel from Greenhill forest who is an old friend of Riliu.