Sarah realizes that Jenna is the missing princess, but decides to keep this a secret from everyone, other than Silas. She mentions that it happened around the time Alther Mella, Marcia's mentor, had been killed. Sally also says that the assassination had occurred months before, but had been kept a secret.

As well, the queen's newborn daughter had gone missing. Months later, Sarah learns from her friend Sally Mullin that the queen has been assassinated, and the castle is under the control of the Supreme Custodian. Silas and his wife, Sarah, decide to raise the baby girl in place of Septimus as if she was their own daughter. Upon reaching his home, Silas sees the midwife run out with a bundle of cloth, wailing that his newborn Septimus, the seventh son of a seventh son, is dead. Silas continues his walk home, to bring his wife the herbs she needs and a new child. Silas agrees as she is the new ExtraOrdinary Wizard. However, he is confronted by the ExtraOrdinary Wizard, Marcia Overstrand, who warns him that he should not tell anyone about the baby he found and that he should say the child was born to him. He hides the baby in his cloak and continues his trek home. Since Silas already has six children and a new one born just that day, he finds that another will do no harm and that his wife, Sarah Heap, will not disagree. As he is walking, he feels a heartbeat in the snow, through Magykal means, and finds that a newborn baby girl with violet eyes has seemingly been abandoned in the snow. The book begins with Silas Heap, father of the eponymous protagonist of the series, returning home through the winter snow.

A moat was built to prevent witches and wolverines from a nearby forest from attacking the inhabitants. It also takes place in a castle simply known as 'The Castle', which started as a small village inside the curve of a river. The story's setting is mainly centred on the Marram Marshes, which is where Aunt Zelda lives. The cover also depicts Septimus's Dragon Ring, rendered as if it were sitting atop the diary. The book cover of Magyk alludes to the diary that the ExtraOrdinary Wizard Marcia makes for her apprentice, Septimus Heap. The sequel, Flyte was released in March 2006, Physik in March 2007, Queste in 2008, Syren in September 2009, Darke in July 2011, and Fyre in 2013. It is the first book in the seven-book Septimus Heap series. Magyk (an archaic spelling of 'Magic') is a fantasy novel written by English author Angie Sage.

Angie sage septimus heap