The ancient custom of spring betrothal allows a man and a woman, by mutual consent, to marry for a time - for one year and one day. Knight Errant Eric of Wycliffe and Lady Rosalind, the young heiress of Stanwood Castle, decide to take this step, seeing in it the only thing salvation from mortal dangers. In the eyes of Rosalind, Eric is a dangerous robber nicknamed the Black Sword, sentenced to hang; however, she hopes that he - in gratitude for getting rid of the noose or counting on a generous reward - will help her and the wounded, helpless page Cleve get to her father's castle. Neither one nor the other intends to fulfill the vows made according to the pagan rite. However, life decided differently.