I've been looking for this manga for years and my memory is starting to fade on it, except I really liked the one (to 3) chapters I read on it. I will tell you as much as I can remember.

The story featured a young girl in a snowy world. She lived in a cabin (either alone or with a single guardian but I think she was alone). She worked/studied for a "sensei" who was a teacher or scientist. She was told not to go to the village at the bottom of her hill/mountain. I forget why. One day a robot/mech boy crashes into her house. He is being chased by a group and in order to save him they both run away towards the village. This is where the manga I had read left off.

I read it years ago, I can't remember any names or manga title. The young girl looked maybe 8-12 with either 1 or two braids, low on her head. She was usually drawn bundled up. The boy looked about her age. Everyone else was adults. I believe the person trying to "recapture" the boy was lead by a woman. And I think her teacher was a man. I feel in the chapter I read she visited him twice.

This is all I can remember. I really wish I knew more and have tried on and off to find it for years. If anyone has any ideas I would be eternally grateful! Thank you so much for your help!