'Gal and Deirdre have forgotten something. Something really, really important.
'When her grandmother dies, Deirdre is left alone in a crumbling block of flats. Looking out the window one misty night, she sees a boy who seems familiar. Together, he and Deirde must discover the secret of the old building, before it collapses and the secret is lost forever . . .' (Publisher's blurb)