Grace first met her lover, Nate, as a teenager, their bond forged in the corridors and waiting rooms where siblings of cancer patients sit on the sidelines. Now an adult, for Grace, nursing is a comforting world of science and certainty. But the paediatric ward is also a place of miracles and heartbreak and, when faced with a dramatic emergency, Grace is confronted with memories of her sister's illness. Heading south to the haunts of her childhood, Grace discovers that a stone cast across a lake sends out ripples long after the stone has gone.