Soukou Senki Prism Breaker ~Seigi no Heroine Kutsujoku no Sennou Saimin Choukyou~

The scientifically advanced Strangers of "Grenada" threaten to destroy our planet.
Between them and us is Hatsune Shindo, a.k.a. Prism Reica of the justice squad.

Joined by her younger sister Hikari, a.k.a. Prism Shine, Hatsune keeps the Strangers at bay,
decimating the small fries and humiliating Damned, the leader of Grenada.
Grenada's mad scientist, Dr. Brain, vows revenge by brainwashing Prism Reica
into a mindless harlot. Perverted to her very soul, she trades justice
for jizzum and plummets like a fallen angel into the miasma of deep pleasure.

Whether she will survive her ordeal and come back from obscenity,
or whether Grenada has ingeniously destroyed Earth's most righteous girl
from the inside out, will only be known in the final hour.

[From DLSite English]