Exiled by the usurper Sligon, the Christian royal family of Scandia—King Aguar, his wife, and their son Prince Valiant—find shelter under the protection of King Arthur. As the young prince grows into a capable man, he is sent to Camelot to begin training under the trusted knight of the Round Table, Sir Gawain.
During his wanderings, Valiant stumbles upon a secret meeting between some of Sligon's Vikings and a black-clad knight. He is spotted but manages to slip away and comes under the care of King Luke. Luke's daughters, Aleta and Ilene, shelter him, and a tender romance soon blossoms between Valiant and Aleta, though Luke's disapproval of Valiant's Viking heritage forces their love to stay hidden. Meanwhile, Ilene grows drawn to Gawain, adding a quiet thread of courtly intrigue to Camelot's life.
Back at Camelot, Valiant learns that Sir Brack had disappeared while pursuing the enigmatic Black Knight, and that Gawain had endured an ambush during that search. Valiant's suspicions rise as he pieces together clues about Brack's fate and the shadowy schemes orbiting the throne.
At a tournament held to honor Aleta, Valiant secretly wears Gawain's armor to compete for the prize. He advances to the joust but is eventually unmasked after losing the match; another contender wins, only to reveal himself later to be Gawain in disguise. Gawain's true feelings for Aleta become clear in that moment, though he keeps his distance to honor his prince's honor.
Awakening on his sickbed, Gawain beholds Aleta and falls in love with her. Out of respect for his patron, Valiant withholds the truth about their relationship from the wounded knight.
A messenger arrives for Brack, and that very night Aguar's seal ring is thrown through the window of Gawain's chambers, signaling that trouble has come to Camelot once more. Realizing his parents are in danger, Valiant prepares to depart for Scandia, but is captured by Sligon's Vikings and Brack, who has betrayed the king to aid Sligon’s bid for power.
Christian Vikings led by Boltar stage a revolt to rescue Aguar's family. Boltar infiltrates the castle to strike at Sligon, encounters Valiant, and urges him to signal the attack once Sligon has fallen. The plan is mis-timed, and the attack comes too soon. Valiant fights to restore order, sets portions of the castle ablaze to breach the walls, and defeats Sligon in the ensuing struggle.
Valiant returns to Camelot with Aleta and confronts Brack's treachery before Arthur and the assembled Round Table. Brack demands a trial by combat; Gawain offers to stand in for Valiant, but the prince insists on his own challenge. In the duel, Valiant kills Brack. With the truth about Brack's betrayal finally laid bare, Gawain blesses the match between Aleta and Valiant, and King Arthur formally greets Valiant as a Knight of the Round Table.
