Nathaniel is taken on when he is very young as an apprentice magician to Mr. Underwood.  Mr. Underwood treats Nathaniel like he will never be anything in the magical community.  Out of rage, one day Nathaniel summons Bartimaeus, with the help books that he sunk out of Mr. Underwood’s office.  Bartimaeus is a djinni, a powerful magical creature.  Nathaniel uses Bartimaeus first to steal the Amulet of Samarakand and to hide it in Mr. Underwood’s office.  The Amulet is in the possession of Simon Lovelace who had originally stolen it from the government.  Simon Lovelace has been secretly planning an attack on the government to kill its leader so he can become the new head of the government.  The attack includes the Amulet so that it will protect him during the assault.  So when it is stolen by Bartimaeus, Lovelace tracks it down to Mr. Underwood’s office.  When Lovelace gets there, he steals the Amulet and kills Mr. Underwood and his wife and tries to kill Nathaniel and Bartimaeus.  The death of Mrs. Underwood greatly angers Nathaniel, because she was the one person who was nice to him.  Now he wants revenge.  He finds out where Lovelace’s attack will take place, and he and Bartimaeus go to stop it.