In the Regild Century, after the Universal Century's space conflicts, Earth enjoys a tranquil period linked to space via the revered Capital Tower. Bellri Zenam, training for the Capital Guard, faces a crisis when the mysterious G-Self attacks the tower. Despite capturing it, Bellri is drawn to Aida Surugan, the daring pilot. As Bellri unlocks the G-Self's secrets, a cascade of revelations threatens the Regild Century's fragile peace.