It will probably be hard to do this in its entirety, but I suggest (that is, if you really want a minor key), Beethoven's Piano Sonata #8 in C Minor, more popularly known as
Sonata Pathetique. Its long, so you'll have no problem finding a good excerpt. As for the melody, it is soft, inviting, but can be dark. Hope this helps.
Here are some links:
1st Movement
This girl is quite moving. She captures the sound emotion very, very well - much better than anyone else I've seen..