The Last Witch of Manhattan — Richard Lewis

Eldie's mother, the last of the Balinese witches, has been abducted out of her Manhattan townhouse. Eldie's explorer father has vanished while searching for his wife. Now somebody wants to kidnap Eldie's invisible friend, Sam. With Sam's help, Eldie must develop her powers in order to rescue her parents and prevent a cosmic rift. But as she discovers, her powers are dark and troubled.