As a child, Nanami was saved by a hero of justice, and captivated by his heroic figure, she vowed to become a warrior of justice herself. Through relentless effort and tireless training, she evolved into Charge Mermaid, proudly fighting alongside her comrades to uphold justice. One day, Nanami discovers her ally Charge Pegasus being chased by a villain. Unaware that this is part of a secret operation, she rushes in to save Pegasus and confronts the enemy. However, she is gravely injured in the villain's attack and falls into danger. Her teammates attempt an emergency change in strategy to defeat the villain, but because Nanami blocks their line of fire by shielding Pegasus, they are unable to attack and the villain escapes. This failure repeats multiple times, and the Charge Man team, pushed to their limits by Nanami's reckless actions, ultimately declare her unfit for combat and remove her from the squad. Determined to regain her place as Charge Mermaid, Nanami resolves to single-handedly destroy the evil organization. But unable to transform in her current state, she is defeated and captured by the villain. The evil organization takes Nanami hostage and uses her to blackmail the Charge Man team. What will become of Aoi Nanami?! [BAD END]