Training The Walker

All her life Cassie has seen strange things. First it was the strangers with feathers and beaks, then there were the normal looking folks who, when her skin touched hers, sent her vision someplace else. Told always to hide what she saw, Cassie worked hard to fly under the radar. But when more of these strange others came to town, hiding became harder and she was caught. Luckily the ones who caught her seem more interested in training her than killing her, at least for now.
She begins her training as one of the mysterious Walkers, but is that really what she is, or is Cassie Wilson something else entirely?