When the King was captured in battle, he sent word to his Queen to sell all they owned and use the money to pay a ransom for his freedom. Realizing there was no safe way for her to do that, she devises a clever plan to free him. By disguising herself as a minstrel and playing the lute beautifully, she makes her way to the foreign land where her King has been imprisoned, charms the lord who holds him, and wins the King's freedom. However, even after he has been released and they have made their way safely home, she does not reveal her identity to him, slipping back into the castle and dressing as herself. This leads to the story's conclusion when the King meets the Queen again, thinking that she had made no effort to save him. He rejects her bitterly until she assumes her minstrel disguise and plays for him; she then drops the disguise, after declaring her love for him. They are reunited to celebrate his rescue and her wisdom.
Why exactly she keeps up her disguise even after the King has been freed and she is safe to reveal her identity is not made clear in the story, but without this deception, the story's theme could not have been developed. Even though her husband treated her bitterly, the Queen does not blame him. He believed that by not ransoming him, she had shown that she loved money more than his life. He never considered any other possibility. He was wrong to have lost faith in her, as he soon discovers. Her love for him was strong enough, however, to forgive him, even though he had doubted her love. The stronger love, the story seems to say, is unconditional, remaining faithful in the face of adversity.