Summary and Preview
An evil organization, whose members are "Phantoms" that look like people in robotic suits, is planning to conquer the Earth. One of them, Phantom Vorken, lives disguised as an ordinary high school boy named Tenkawa Toichi. One day, the cute transfer student Maishima Kokoro, who claims to have no interest in boring things like romance and lust, joins his class.
Secretly, she is the last defense of mankind against this evil army. When danger appears, she transforms into Mighty Heart, an angel who condemns evildoers! ...Unfortunately, despite all her talk, she's so weak she never really stands a chance against anyone. However, she does have one very powerful weapon, which only comes out when she's feeling incredibly shy and embarrassed. At the peak of her embarrassment she releases her "Mighty Beam." This weapon can reach a devastating power equivalent to several tons of TNT, provided she cries from the shame. Her embarrassment, typically brought on by some form of sexual situation, can win any fight!
As Tenkawa gets to know Maishima, both in school and during their alter egos' fights, he can't help himself wanting to protect the adorable, well-meaning, and mostly helpless heroine. Will he be able to stick to his role as the evil Phantom fighting this heroine of justice?