Margaret Marshall’s husband went into cardiac arrest on a train when a complete stranger gave her husband CPR continuously until the train was able to pull in at a train station. The husband had no memory of the incident or the stranger. She was told that if this person had not done what he did, he would have died. She knew this person had to have had some training to do what he did but who was this person? Where did he get the training? Margaret turned to Facebook to find the man and when she found him, she was able to learn the secret to how this stranger knew how to save her husband’s life.