Merlin, the mentor of King Arthur while he was still a youth, summons Rowena and Robin from the future, so that Robin can help train him in combat. Morganna, Merlin's archenemy, wants to kill Arthur, so that the Black Knight can win Excalibur and become king. Robin helps Arthur fulfill his destiny.

Lord Cloughton arranges a summit with three important Normans to conspire with the Saxons against King John. Each member of Robin's band undertakes to fetch one of the participants, protecting them from the men of Count Rood, who wants to prevent the meeting: Robin fetches the suspicious and reluctant Countess DuMonde, Marion fetches the agoraphobic young Count Lucerne, and Friar Tuck fetches Count Brouchard (who turns out to be Barkley), while Little John protects Lord Cloughton. Rood hires a mysterious assassin, who can morph into many different people and creatures, to help prevent the meeting.