A'Choille Fhiadhach by Kenneth Lindsay
Ostracised at school because of her parents' eccentricity, Anna coped by inventing an imaginary friend called Pipkin, but when she started chatting to boys on the internet she soon forgot her childhood companion. Now a fuel crisis has thrown the island into chaos, leaving Anna without her social lifeline, and suddenly Pipkin is back, but this time he's real and more sinister than she ever dreamt he could be.