Newport County, Derby County, Luton Town and more. Open heart surgery at 16 and 27 years old. Told you only have a certain amount of time to live. Told you won't make it in professional football. Playing over 200 pro games. This is part one of a class conversation with Mark O'Brien, 3 years after retirement, and 13 years after making his debut for Derby County at 16. One hell of a journey!