The Borrowing Ghost. Jitter Jumpers, #13

Thirteen-year-old Raina knows the rhythms of her home by heart: the ticking clocks, the rustling willow, and the gentle absent-mindedness of her grandfather, Arthur. But when her favorite cerulean pencil vanishes into thin air, followed by a silver thimble and a faded blue ribbon, Raina realizes something, or someone, is "borrowing" her life. Her search leads to a dusty attic and a hidden "hoard" of lost treasures.
To solve the mystery of the "Borrowing Ghost, " Raina must uncover a sixty-year-old secret that her grandfather has desperately tried to keep buried.