Bo finally learns the identity of her mother � and that those closest to her have been keeping secrets. No longer sure who to trust, Bo decides to track down �Mommy Dearest� alone, in order to extract the truth about her own origins once and for all. While everyone frantically searches for Bo, Dyson visits an ancient Norn, a wish-granting, tree-dwelling crone, where � in order to protect the woman he loves — he makes a sacrifice that may change his relationship with Bo forever, as she prepares for a final face off with her deadly mother.