The Thirteenth Stone was a made-for-audio Sarah Jane Adventures audiobook written by Justin Richards, produced for BBC Audio and read by Elisabeth Sladen. It accompanied the CBBC broadcast of series 1.
Sarah Jane is helping out on a school trip with Luke, Maria, and Clyde's class. On the way home, the group stop off at the Stone Whisperers, a dozen standing stones enclosed by a dome. Set apart from the circle is a thirteenth stone: the King Stone. Legend has it that this is an evil king who was captured in battle by twelve knights, and turned to stone. To keep him imprisoned, the knights too turned to stone, holding him forever in their power. Nice story, but it's just a myth — isn't it?
Luke finds himself strangely drawn to the King Stone. Over two metres high, and covered in moss, it glows with a strange, unearthly light. But when the secret of the stones is finally revealed, the school party's enthusiasm turns to terror.
Clyde, Luke and Maria are on a class trip with their teachers Mr Bradbury and Mrs Reiki. Sarah Jane Smith accompanies the class. After visiting the St Margaret's House Museum the class is going to the Stone Whisperers, a semi-circle of twelve stones. Set apart from the circle is a thirteenth stone: the King Stone. According to a myth this stone is an ancient warrior king who was captured by the twelve knights that form the circle.
Professor Jacqueline Lauton invites the children to see the computer lab, where radar scans of the stones are about to be fully analysed. When this occurs, they see that there are humanoid figures in the centre of the stones, one of whom, Ravage, escapes and takes possession of Luke.
The other stones wake up as well. They turn out to be warriors and want to capture Ravage. The warriors had previously imprisoned Ravage and wanted to trap for all eternity inside a stone. They sacrificed themselves, gave up their remaining life-force to keep Ravage in prison. The warriors were arranged to focus their energy on the stone where Ravage was held. After Ravage has escaped all they want is to capture him again. Sarah Jane, Maria and Clyde are afraid that they might hurt the possessed Luke and try to save Luke from the warriors. They also realise that Luke is able to get back the control over himself when they ask him mathematical questions, so they ask him about the complete number of pi and other things.
Later they find out that Ravage has possessed Luke because Luke hasn't existed for long. Luke has new unformed, impressionable mind. He hasn't had a lot of experience and his personality was still forming. So it was easy for Ravage to take over Luke. Sarah Jane tells Luke that she knows that Luke can drive Ravage out of his mind and that she, Maria and Clyde will help Luke. Then Sarah Jane and Maria speak to the warriors to tell them not to hurt Luke because they are sure that he can fight Ravage. The warriors stop fighting Luke.
Now Sarah Jane speaks to Luke she tells him that she can't do it for him. She adds that she has to let him go and let him be himself, because that's what he needs to do. Luke's eyes are wide and afraid but then he screams "Get out of me, Ravage!". Then Luke says that he is Luke, that he knows who he is and that Ravage can't take that away from him. He adds that he has his own life. Then he looks at Maria and Sarah Jane saying he has his own friends and his own mother. Finally, Ravage is defeated, he is expelled from Luke's mind and dies.
All around Sarah Jane, Maria and Luke the warriors slowly bow their heads. They lower their swords and kneel on one knee as if paying homage to Luke, to the boy who had finally defeated Ravage. Clyde is coming down from the walkway. The kneeling warriors are turning back into stones. Sarah Jane, Maria, Clyde and Luke are standing in the middle of a circle of stones when Professor Jacqueline Lauton arrives. As Prof. Lauton expected a semi-circle of stones and not a circle she is standing there starring, mouth open, then she turns and goes back into the computer room to analys the new data.
The main doors are swinging open and Professor Riley and Mr Bradbury arrive. Sarah Jane tells them that nothing special had happened. The thirteenth stone has just lost its inexplicable glow. She adds that the stones have moved because of a "ravage storm", which was a freak magnetic pulse from the thunderclouds coupled with the power surge. Prof. Riley says he has never heard of such a storm. Clyde replies that it is for sure that these stones didn't move on their own.
- Sarah Jane Smith
- Maria Jackson
- Luke Smith
- Clyde Langer
- Mr Bradbury
- Mr Riley
- Jacqueline Lauton
- Mrs Reiki
- Mr Bradbury's history class visited the St Margaret's House Museum and the Stone Whisperers.
- Amital is the home planet of Ravage and the Stone Warriors.
- Mr Bradbury is fascinated of the archaeological burial site Sutton Hoo.
- Brasília is the capital of the South American country Brazil.
to be added
- Sarah Jane mentions visiting medieval times (TV: The Time Warrior) and the Victorian era (PROSE: The Lampblack Wars, Evolution).