The Devil's Bride - S2.E3

Marion is abducted by Brother Groliet, an evil member of the God of Death cult. She is intended to become the bride of Balor, the Prince of Darkness, to have a child and give him the power of eternal life. Marion refuses, and is cast into a deep spell. Only Robin can obtain the horn of a unicorn, which is the only source of power strong enough to destroy the evil Lord of Death