At 5 years old, Nathanial is sold by his parents to an angry and pathetic magician( Mr. Underwood). He starts to learn the basics of magic.
At a gathering of magicians, Nathanial gets embarrassed by Simon Lovelace, a senior magician, and gets sent to his room. He got so mad that he released some magical insects that's sting hurt like a million bees. After that, the magician killed the insects and embarrassed him again. Nathanial swore revenge on that day.
He worked hard on a revenge scheme and finally decided to summon Bartimaeus, a very powerful djinn, and decides to take an amulet from Simon Lovelace who embarrassed him at that party about two years ago. The plan was successful.
Bartimaeus went and stole a powerful amulet from Simon Lovelace, the powerful magician that embarrassed Nathanial years ago. Little did Nathanial know Simon needed that amulet for his master plan.
Simon Lovelace finally found the amulet and killed everybody in the house. Nathanial's master died and so did his wife but Nathanial had Bartimaeus there to protect himself. While this is happening Nathanial figures out Simon Lovelace has a plan to kill all of parliament and take over and he must stop it.
Bartimaeus and Nathanial go to Simon's home where he is supposed to kill all of the parliament at a luscious party. They steal the amulet, defeat Simon's demon that he summons and put an end to Simon Lovelace's plan to take control.