Plot: For six months, nine-year-old David Stocker had been in and out of hospital with a debilitating but mystery illness. His condition baffled doctors at Great Ormond Street and he was put on a drip - but what the medical staff didn't know was that David was being slowly and systematically poisoned by his attentive but deranged mother, Petrina, a long-term sufferer of Munchausen's Syndrome