"Kidō Senshi Gundam AGE: Tsuioku no Shido" is a manga adaptation set in the "Mobile Suit Gundam AGE" universe, serving as a prequel to the main anime series. The story explores the origins of the Gundam AGE-1 and the early days of the war between humanity and the mysterious alien race known as the UE (Unknown Enemy). The narrative centers on Flit Asuno, a young engineer and the protagonist of the series, whose life is shaped by tragedy and a relentless drive to protect humanity.

The manga begins with Flit as a child living on the colony of Ovan, where he witnesses the devastating UE attack that destroys his home and kills his mother. This traumatic event becomes the catalyst for his determination to develop a weapon capable of defending humanity. Flit inherits the AGE Device, a powerful technological artifact left by his ancestors, which contains the knowledge to create advanced mobile suits. With the help of his mentor, Ract Elfamel, Flit dedicates himself to engineering the Gundam AGE-1, a mobile suit designed to combat the UE threat.

As Flit grows older, he becomes a key figure in the Earth Federation's efforts to resist the UE. The story delves into his struggles to balance his personal vendetta with his responsibilities as a leader and engineer. Alongside Flit, the manga introduces other significant characters, such as Emily Amonde, his childhood friend and eventual love interest, and Woolf Enneacle, a skilled mobile suit pilot who becomes an ally in the fight against the UE. The narrative also explores the broader conflict, highlighting the political and military tensions within the Earth Federation as they grapple with the existential threat posed by the UE.

The manga provides a detailed look at the development of the Gundam AGE-1, showcasing Flit's ingenuity and the challenges he faces in perfecting the machine. It also examines the moral complexities of warfare, as Flit's desire for vengeance is tempered by his growing understanding of the cost of conflict. The UE, initially portrayed as a faceless enemy, are gradually revealed to have their own motivations and history, adding depth to the overarching conflict.

"Kidō Senshi Gundam AGE: Tsuioku no Shido" serves as a foundational piece of the Gundam AGE timeline, offering insight into the events that set the stage for the anime series. It combines themes of loss, resilience, and technological innovation, while maintaining a focus on the human element of war. The manga provides a compelling exploration of Flit Asuno's journey from a grieving child to a determined engineer and leader, laying the groundwork for the larger narrative of the Gundam AGE saga.