Caliph Harun al-Rashid learns of a murder and commands that his vizier Ja'far solve the case in three days. It turns out that a man killed his wife. He brought her three apples when she was sick, and then later noticed a slave with one of the apples. The slave claimed it was a gift from his mistress. Believing that his wife was unfaithful, he then cut her into pieces, put the pieces into a chest, and threw the chest into the river. Upon returning home, however, he learned the truth - the slave did not receive the apple from his wife, but stole it from his son.
The Caliph spares the murderer and tells Ja'far that he must find the slave in three days or die. Ja'far knows that it is a hopeless task, but on the third day, his daughter shows him an apple that she bought from their slave Rayhan. He takes the slave to the Sultan, but it is then agreed that Ja'far will tell the Tale of Núr al-Dín Alí and his Son. If it is more wondrous than the story of the three apples, then the slave may live.