One bleak, late winter's day, Julie Myerson finds herself in a graveyard, looking for traces of a young woman who died nearly two centuries before. As a child in Regency England, Mary Yelloly painted an exquisite album of watercolours that uniquely reflected the world she lived in. But Mary died at the age of twenty-one, and when Julie comes across this album, she is haunted by the potential never realised, the barely-lived life cut short.

And most of all, she is reminded of her own child.

Because only days earlier, Julie and her husband locked their eldest son out of the family home. He was just seventeen. How could it have come to this? After a happy growing-up, it had taken only a matter of months for this bright, sweet, good-humoured boy to completely lose his way and propel his family into daily chaos. He had discovered cannabis and was now smoking it everyday - and nothing they could say or do, no help they could offer, seemed to reach him. And Julie - whose emotionally fragile relationship with her own father had left her determined to love her children better - had to accept that she was, for the moment at least, powerless to bring back the boy she had known.

Honest, warm and often profoundly upsetting, this is the parallel story of a girl and a boy separated by centuries. The circumstances are very different, but the questions remain terrifyingly the same. What happens when a child disappears from a family? What will survive of any of us in memory or in history? And how is a mother to cope when love - however absolute, however unconditional - is not enough to save her child?