The Lives is set in a world quite different from ours, during the adolescence of Christopher Chant who is Chrestomanci in five of the books.

Worlds have branched from common ancestors at important events in history, such as English and French victories in the Battle of Agincourt.

World 12A is the primary specific setting of this volume, and of the series, where Chrestomanci resides in England.

The novel tells the story of Christopher Chant's childhood in a magic filled Victorian style era.

Although both of his parents are powerful practitioners of magic, the two are constantly at loggerheads; his father (an enchanter, the strongest type of magic-user) is entirely devoted to his work, to such a degree that the young Christopher is afraid that he would not recognise him should the two meet in public.

He makes a deal with her for one of her magic temple cats, Throgmorten, but as she helps him escape he is speared by one of her many guards.

After waking up in his bed with Throgmorten, Christopher accidentally causes a curtain rod to fall down and spear him through the heart, although he survives.

This experience prompts his parents to send him to a boarding school where Christopher forgets to travel in his dreams because he enjoys it so much.

Several ordinary months go by and Christopher decides to become a professional cricketer whilst his parents divorce.

The current Chrestomanci named Gabriel De Witt visits him, but disbelieves claims of him being an enchanter.

Christopher discovers that Chrestomanci is investigating a smuggler named 'The Wraith' who somehow manages to bring illegal items from other worlds.

Millie discovers that Asheth is too vain to actually give a mortal girl magic and she is in reality one of the most powerful enchantresses in existence.

Learning that Mordecai is enchanted to work for Ralph, Christopher and Millie travel to world 11 which is a mysterious place that only has one timeline.

Christopher and Millie are both able to outwit the ruler of World 11 and free Mordecai, who willingly becomes a servant of Chrestomanci.

Christopher is discovered to be the next Chrestomanci when his best friend hits him in the head with a cricket bat by accident, killing him.

She winds up living in Christopher's world, going to school like an ordinary, wealthy girl with the funds the chief priestess gives her from the Temple.

In the short story Stealer of Souls it is implied that Tacroy and Miss Rosalie marry and look after Gabriel de Witt once he has retired from the post of Chrestomanci.

Uncle Ralph also happens to be the leader of the Wraith, an underground criminal organisation that smuggles magical goods and sells them through the black market.