"Saint Seiya: The Lost Canvas - Meiō Shinwa" is a prequel to the original "Saint Seiya" series, set in the 18th century during the Holy War between Athena and Hades. The story centers on Tenma, a young boy from Italy who becomes the Pegasus Saint, and his childhood friend Alone, who is revealed to be the reincarnation of Hades. The narrative explores their intertwined fates as they find themselves on opposing sides of the conflict.

The Holy War begins when Hades awakens and gathers his 108 Specters to wage war against Athena and her Saints. Tenma, alongside other Saints such as Sasha (Athena’s reincarnation), Dohko of Libra, and Shion of Aries, fights to protect humanity and prevent Hades from plunging the world into darkness. Alone, manipulated by the spirit of Hades, becomes the vessel for the god of the underworld, setting the stage for a tragic confrontation between the two friends.

The story is structured around the Saints’ efforts to infiltrate Hades’ stronghold, the Lost Canvas, a surreal dimension created by Hades to trap the souls of the dead. Each arc focuses on the battles between the Saints and Hades’ elite Specters, known as the 108 Stars of Destiny. Key battles highlight the sacrifices and camaraderie of the Saints, as well as the emotional turmoil of Tenma, who struggles to reconcile his duty as a Saint with his desire to save Alone from Hades’ influence.

Throughout the series, the narrative delves into the backstories of various characters, including the Gold Saints, who play pivotal roles in the war. Characters like El Cid of Capricorn, Manigoldo of Cancer, and Asmita of Virgo are given significant development, showcasing their unique abilities and personal motivations. The series also explores the concept of reincarnation and the cyclical nature of the Holy War, emphasizing the recurring themes of fate, loyalty, and redemption.

The climax of the story revolves around the final battle within the Lost Canvas, where Tenma confronts Alone in a desperate attempt to sever Hades’ control over him. The resolution of their conflict carries profound consequences for both the characters and the world, ultimately shaping the events of the original "Saint Seiya" timeline. The series concludes with a bittersweet tone, underscoring the enduring legacy of the Saints’ sacrifices and the unbreakable bonds forged in the face of overwhelming adversity.