In a remote part of New Zealand, lies a cold, dark and mysterious cave system with the potential to be the deepest in the world. It’s here that explorer Richard Harris is searching for a sense of self worth. There’s no question that this is the highest stakes dive he has ever done. But there are consequences if it goes wrong. Underground, underwater, with a finite amount of gas to breathe. It’s a dangerous game to play because he is never really satisfied. So what is it that makes him continue with this selfish pursuit when he knows what the cost is to him and those he loves?