Nathaniel is a young magician adopted by Arthur Underwood, an unimportant magician in the internal affairs ministry, which attempts to deal with, among other things, the “resistance”, a group of non-magicians, or “commoners” who seek to overthrow the magician government of Britain. Underwood is despised by his apprentice for his lack of skill, praise and for his inflated view of himself, must of all though, Nathaniel dislikes him for his failure to protect him from Simon Lovelace, a important Magician who had humiliated Nathaniel.
Nathaniel plots his revenge alone, he summons up a spirit, all magicians get most their powers from the demons they summon, this particular one was a Djinn, fairly high ranking among Demons the Djinn could as well as other abilities, shape shift. Summoning one should have been far above Nathaniel, but he did it though years of studying books, his choose, also well studied, was Bartimaeus, upon its arrival the Djinni attempted to trick Nathaniel into stepping outside his protective circle, if he had the demon would have fallen upon him and devoured him. But the twelve-year old persevered, and commanded Bartimaeus to steal the Amulet of Samarkand from Lovelace's possession.
The Amulet was a power full magical artefact that protected its wear against magical attacks, Nathaniel had observed Lovelace stealing it recently, indirectly killing a high ranking magician in the process. His plan was to reveal Lovelace as a traitor in front of the government.
Bartimaeus stole the Amulet, not without drama, and returned it to Underwood's house secreting it in his cellar on Nathaniel command, during this time Bartimaeus found out Nathaniels name, something that meant that it was now nigh impossible for Nathaniel to harm the Demon magically.
Nathaniel Cleverly negotiated around this. Soon however, Lovelace, aware of the theft of the Amulet paid Underwood a visit, killing him and his wife, as well as burning the house to the ground. Nathaniel and Bartimaeus were now on the run from Lovelaces demons, still determined Nathaniel set out for the a huge country house where Lovelace was due to hold a government conference, Nathaniel was convinced Lovelace would try something. Nathaniel and Bartimaeus infiltrated the house, only to find themselves locked in the room of the conference with all the major magicians of the British Empire, including Rupert Devereux, the prime minister. Lovelace's plan soon becomes clear, he intended to summon a demon of massive power, he himself would be Protected by the amulet, whilst the demon wreaked havoc upon the other occupants of the conference hall, once the demon was summoned Nathaniel managed to steal the Amulet. Upon which the demon killed Lovelace, and then was returned to its home “the other place”, the dwelling of all Demons by Nathaniel.
Nathaniel was appointed a new master, Jessica Whitwell, Nathaniel, who has now received his adult name, John Mandrake, then dismisses Bartimaeus, before departing the Demon warns Mandrake of the dangers of being sucked into the selfish government of Britain, where the magicians only ever acted in the own interests.