In Alice's Adventures in Wonderland, the knave of hearts is a character who is accused of stealing tarts belonging to the Queen of Hearts. The knave of hearts is a man who serves as a low-level servant to the Queen of Hearts, and he is known for being dishonest and sneaky.
One day, the Queen of Hearts discovers that her tarts are missing and assumes that the knave of hearts is the one who stole them. She becomes very angry and demands that the knave be brought before her to face punishment. Alice, who has been watching all of this, decides to help the knave by finding the real culprit.
After a lot of searching and questioning, Alice eventually discovers that the tarts were actually stolen by the Knave's former lover, the Knave of spades. When this information is brought to the Queen of hearts, she is very happy and decides to pardon the knave of hearts and punish the knave of spades instead.
So the knave of hearts is ultimately shown to be innocent, and Alice learns a valuable lesson about the importance of seeking the truth before judging someone.