Yui Aikawa,Sayuri Ichimatsu in Step sister Maria's Cross Examination

A nun who's a super heroine! In a radical secret society, in order to regain the holy grail after it was stolen, Sister Maria (played by Yui Aikawa) becomes a super heroine to try to catch the fake priest who stole the holy grail. Along the way, she bumps into Sister Ellis (Sayuri Ichimatsu) who joins in her the quest, which sort of ends with a pretty bad ending.