"Mobile Suit Gundam: Iron-Blooded Orphans" is set in a post-apocalyptic future where humanity has colonized Mars and other celestial bodies. The story begins on Mars, where economic disparity and exploitation by Earth's ruling powers have created a harsh environment for its inhabitants. The central narrative revolves around a group of child soldiers and laborers from the Martian independence movement, who form a private security company called Tekkadan after a failed uprising against their oppressors.

The protagonist, Mikazuki Augus, is a skilled but emotionally detached pilot of the Gundam Barbatos, a powerful mobile suit with a mysterious past. Orga Itsuka, the charismatic leader of Tekkadan, serves as Mikazuki's close friend and strategist, guiding the group's ambitions to secure a better future for themselves and their comrades. Together, they navigate a complex web of political intrigue, corporate warfare, and personal struggles as they fight for independence and recognition in a world dominated by powerful factions.

The series explores themes of loyalty, survival, and the cost of ambition. Tekkadan's rise to prominence attracts the attention of major players, including the Earth-based economic bloc Gjallarhorn, which seeks to maintain its dominance over the solar system. As Tekkadan takes on increasingly dangerous missions, alliances are forged and broken, and the group faces moral dilemmas that test their unity and resolve. Key characters such as Kudelia Aina Bernstein, a Martian noblewoman advocating for independence, and McGillis Fareed, a Gjallarhorn officer with his own hidden agenda, play pivotal roles in shaping the conflict.

The narrative is marked by intense battles, strategic maneuvering, and the personal growth of its characters. Mikazuki's relationship with Atra Mixta, a kind-hearted girl who supports him emotionally, and his unwavering loyalty to Orga highlight the human element amidst the larger-scale conflicts. The series also delves into the consequences of war, as Tekkadan's members grapple with loss, trauma, and the sacrifices required to achieve their goals.

"Iron-Blooded Orphans" distinguishes itself with a grounded approach to the Gundam franchise, emphasizing the struggles of its underdog protagonists and the harsh realities of their world. The story builds toward a climactic confrontation that challenges the ideals and resolve of all involved, leaving a lasting impact on the characters and the world they inhabit.