Seiryu Tenmyoin, the exemplary student body president of Velnar College, is targeted by the sinister Dark Mother organization and their executive, Nailkaizer. After being captured and tortured in an attempt to uncover the identity of the mysterious hero Angel Blade, Seiryu is rescued by the warrior herself. However, the encounter leaves Seiryu unexpectedly transformed into the physical manifestation of Angel Blade, drawing her into a perilous conflict against the monstrous GeoBloods.
Moena struggles to reconcile her identity as the warrior Angel Blade while the forces of Dark Mother, led by General Chloe and Colonel Elaine, plot to capture her. After receiving the completed Angel Heart and a poignant message from her late mother, Moena finds the resolve to embrace her destiny. She transforms to rescue an innocent captive and engage in a fierce battle against the dark mutants.
After a brief encounter with the prototype warrior Angel Ender, Angel Blade falls into a sadistic trap set by Nailkaizer, who uses Seiru as bait. Though Nailkaizer attempts to drain Blade's strength and humiliate her, the intense desire to protect her sister triggers a massive surge of hidden power. Blade unleashes her true potential to defeat her foes, while mysterious observers reveal that she is a test subject for the "Angel System."