The day of the djinn warriors / Kerr, Philip

After getting help for their father, who is cursed with rapid aging, twelve-year-old djinn twins John and Philippa and friends travel through the spirit world in search of Faustina, the only one who can keep their mother from becoming the Blue Djinn, and discover a link to museum thefts and hauntings throughout the word.

Twins John and Philippa Gaunt set out on a dangerous journey around the world as they race to save their mother from her destiny as the Blue Djinn of Babylon, their father from a curse, and museums from a series of strange hauntings and unexplained robberies, and, in the course of their travels, discover an evil force that is is filling the world with wicked spirits.