A band of Vikings capture Prince John, to hold him for ransom, and Robin, who is out hunting with Little John. Robin and his men enable Prince John's escape, but will he live up to his promise to pardon Robin and his men?

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

The slavetrader Brand kidnaps Robin's friend Kemal and his bride, Princess Kadija, and plans to auction them. Marion also has a score to settle with him, from her distant past. Robin and his band pretend to be rich bidders, as part of the scheme to free the two prisoners and get Marion's revenge. But Brand escapes with Kadija into the Forbidden Zone, where Robin and his band are forced to follow and battle him.