 Gary (Eccleston) is wheelchair bound and awaiting a heart transplant. When a young man, Sean, is killed in a motorbike accident, Gary receives his heart. Maria (Reeves), Sean s mother, tracks down the man with her son s heart and gets to know him and his wife, Tess (Hardie). Maria s obsession with the only piece of her son still living is the centre-piece to this unique psychological thriller.