I read this story years ago, and can't find it now A brief overview of the story: Voldemort won, and took over England. Harry Potter and the Ministry fled to the US. Voldemort tells the Minister that he wants something that they had, and that the only one he would accept delivering it was Harry. The minister decides to send Harry with the device, and Voldemort takes Harry back to Hogwarts, and tortures him in Gryffindor. He also has Draco there, but Draco is treated like a prince because he is the "heir apparent" for Voldemort (but that doesn't mean he is going to inherit anything. Instead, Voldemort is feeding him power from many different sources to make him very very powerful, and using Dark Magic is going to take over his body so that he is young again.) The rest that I can remember is only bits and pieces, but I know it is a very long story (I believe there is a sequel too) and that Harry is led around on a collar like a dog and tortured with a fake fire spell (He feels like he's being burned, but there is no real damage)
If anyone knows the name to this fanfic, and/or has a link it'd be much appreciated.