Athletic high school girls are being abducted by a mysterious organization known as The Clown' that turns them into soulless super-soldiers in a bid to take over the world. Due to a mix-up, bumbling athlete Hoshino is abducted and given superpowers by The Clown, but is rescued from the facility by her gym teacher before 'brain wash surgery' can be performed to complete her transformation, and vows to battle the organization and its 'monster killers' to the very end as The Masked Girl.
This one-off tokusatsu production feels like a pilot that didn't get sent to series. I'm not sure if that's how these things work in Japan, but based on its 44-minute run time, it certainly feels like the case. The 2009 Hong Kong DVD on which I watched this lists a 90 minute run time on the case, but that's comprised of this single episode plus a 45-minute making of documentary.
The plot of the episode itself is simplistic and the characters severely underwritten with virtually zero development aside from gaining powers, and it's slowly paced, with the only twist being the revelation that people the heroine knows have also been influenced by the evil Clown organization. Beyond that and a couple of elaborate 'hero' costumes - particularly the Masked Girl's eventual 'plastic-armor-and-leather-strapping-on-a-bodysuit' get-up, capped with an imposing helmet and visor - this is a pretty middle-of-the-road affair, indistinguishable from countless others that likely did go on to become series but never flourished.