Synopsis: "Thomas Young has no idea where he comes from. Found living on the streets as a child and put into foster care, he always dreamed of having a family of his own. Now a grown man, he has his much longed for family, but his life is tinged with sadness. His son, David, has leukemia. One night, as he's driving home from the hospital, he hits a homeless man, Mack, with his car. Mack knows Tom from his childhood and tells Tom he was once part of London's underground homeless and his son's leukemia is not all it seems. In a desperate bid to save his son's life, Tom heads down into the miles of abandoned tubes lines and stations. But he quickly discovers something far more sinister waits for him than the giant rats, drug addicts and fast trains. There is also something dark and shadowy, and it wants out..." – quoted from this book's product page on Amazon.com as of 2017-12-23.