Physik (Septimus Heap, Bk. 3)

When Silas Heap unseals a forgotten room in the Palace, he releases the ghost of a Queen who lived five hundred years earlier. Queen Etheldredda is as awful in death as she was in life, and she's still up to no good. Her diabolical plan to give herself everlasting life requires Jenna's compliance, Septimus's disappearance, and the talents of her son, Marcellus Pye, a famous Alchemist and Physician. And if Queen Etheldredda's plot involves Jenna and Septimus, then it will surely involve Nicko, Alther Mella, Marcia Overstrand, Beetle, Stanley, Sarah, Silas, Spit Fyre, Aunt Zelda.