I remember the anime series revolving around two girls, an older and a younger one. The younger one was some kind of android of sorts and she was sad because she wanted a heart.
The girls were both dressed as maids and the younger girl had short orange hair.
It was an older anime for sure, I must have watched it around late 90's or early 00's.
At the end of the anime, the younger android girl went into some kind of facility, probably a government facility, for some reason.
I vividly remember the ending being a bit violent, the older girl (I think she was an android too but with a heart) came to save the younger girl and they were falling down a huge circular pit type thing while being shot at.
I am pretty sure they survived but I cannot remember the name!