"Saint Elmo - Hikari no Raihousha" is a science fiction anime series set in a futuristic world where humanity faces an existential threat from mysterious, otherworldly entities known as the "Visitors." These beings, emerging from a dimensional rift, possess advanced technology and destructive capabilities that far surpass human understanding. The story centers on the efforts of the human resistance, particularly the elite unit known as Saint Elmo, tasked with combating the Visitors and uncovering the truth behind their invasion.

The protagonist, Akira Kamishiro, is a skilled pilot and a key member of Saint Elmo. Akira is driven by a personal vendetta against the Visitors, having lost his family during one of their initial attacks. His determination and combat prowess make him a central figure in the fight against the invaders. Alongside Akira is a diverse team of pilots, scientists, and strategists, each contributing unique skills and perspectives to the mission. Among them is Rina Tachibana, a brilliant engineer who develops advanced weaponry and mecha units to counter the Visitors' superior technology. Her inventions, particularly the high-performance mecha "Elmo Frame," become crucial assets in the battle.

The narrative unfolds as Saint Elmo uncovers deeper layers of the Visitors' origins and motives. Through a series of intense battles and strategic missions, the team discovers that the Visitors are not merely invaders but remnants of an ancient civilization seeking to reclaim their lost world. This revelation complicates the conflict, as it raises questions about humanity's role in the broader cosmic struggle. The series explores themes of survival, sacrifice, and the moral ambiguities of war, as the characters grapple with the consequences of their actions and the blurred lines between right and wrong.

As the story progresses, Akira and his comrades face increasingly formidable foes, including rogue factions within the human resistance and enigmatic Visitors with their own agendas. The series builds toward a climactic confrontation that tests the limits of human ingenuity and resilience. Through its intricate plot and well-developed characters, "Saint Elmo - Hikari no Raihousha" presents a compelling exploration of humanity's struggle against overwhelming odds and the enduring quest for understanding in the face of the unknown.