Tanith Lee 
East of Midnight 

Dekteon is a slave on the run, exhausted, beaten, pursued by his master’s dogs. When the eerie horse and cart appear through the trees, and its hooded driver offers him shelter, he has no choice but to accept. But as the cart rolls slowly through the mist, Dekteon becomes uneasy. Who would want to befriend a desperate fugitive? Surely only someone whose own future is even more dreadful than his own?