The Firma Twins and the Purple Staff of Death

Born into a family of twins, Isis Firma and her identical twin sister Electra are as different as two people can be. Isis is studious and quiet; Electra is an outgoing athlete.
On their twelfth birthday, Isis decides, much to Electra’s disgust, that they and their friends will celebrate by viewing a just autopsied mummy at the Institute of Ancient Egyptian Stuff in nearby Washington, DC.
Unseen by everyone except Isis, the mummy sits up and tells her to find the Purple Staff of Death. Danger threatens as Isis, her sister, and friends unravel the mystery of the mummy's message and the secrets of the Firma family.