A young man, Richard Cypher, rescues a woman from 4 men who are following her. The woman tells him she is searching for a wizard. Richard helps Kahlan, the woman, to find the wizard, so he can appoint a seeker of truth. Richard is appointed seeker by Zeddicus Zu'll Zorander, the First Wizard of the Midlands. The three of them head off to fight the evil Lord Rahl of D'hara. On one point in the book, Richard is captured by a Mord-Sith, an torturer who works for Lord Rahl. He is tortured to tell Lord Rahl wat the Book of Counted Shadows say, because Richard learned what it says when he was just a kid.
Richard is now the Lord Rahl of D'hara, because Darken Rahl, the evil Lord Rahl from the Wizard's First Rule, raped his mother, the daughter of Zedd. Richard is taken by the Sisters of the Light, so they can teach him how to use his magic. Kahlan goes to the capital of the Midlands, because she, as the Mother Confessor, has to lead the Central Council. Zedd stays at the People's Palace, and is attacked by several beasts from the Underworld. Richard has to fight off several Sisters of the Dark, who have infiltrated the Sisters of the Light, and are stealing the magic of the young wizards.
For more information about the other 9 books, or about Terry Goodkind: http://www.terrygoodkind.com/