The daughter of King Neptune takes on human form to avenge the death of her young sister, who was caught in a fishing net. However, she falls in love with the king, the man she holds responsible.
Wilfred of Ivanhoe (played by King Baggot), son of Sir Cedric (played by Wallace Bosco), returns to England from the Crusades in the Holy Land. As Ivanhoe, disguised, discovers that his beloved Lady Rowena (played by Evelyn Hope) has remained faithful, two weary travelers, Isaac of York (played by Herbert Brenon) and his pretty daughter Rebecca (played by Leah Baird), are admitted to Sir Cedric's castle, but after the knights learn that Isaac has money they abduct the visitors to the Norman stronghold of Torquilstone Castle.
