A mother tests a weapon she knows will kill her. Four-year-old Miorine watches from across an asteroid while her mother walks toward a Gundam that doesn't care about her birthday. The prologue refuses to make this melodrama, it treats sacrifice like mathematics, then shows you the human cost in a child's face. The animation moves like it understands what it means to lose someone before you even know them. This is a prelude that works backwards from the ending, building dread through fluid mecha sequences and a soundtrack that knows exactly when to break your heart. By the time Elnora steps into the Lfrith, you already understand what Miorine becomes.

At Fólkvangr, a front built inside an asteroid, test pilot Elnora Samaya runs operating trials of the Gundam Lfrith at the Vanadis Institute's laboratory, watched by the machine's creator, Cardo Nabo. The Lfrith still falls short of the conditions set by the council, and Elnora is losing patience. The same day is her daughter Ericht's fourth birthday. Ignoring orders to stay away, Ericht comes to see her mother at work, forms a strange bond with the mecha, and chaos follows. This one-episode mecha special serves as the prologue to The Witch from Mercury.