In 2003, Rebecca Whitaker died in a road accident. Her husband Mark is still grieving. Then he receives a battered envelope, posted eight years ago, containing a set of instructions and a letter with a simple message: "You can save her." Later that night, while picking up a takeaway, Mark glances at a security monitor - to see himself, standing in the restaurant in grainy black and white. And behind him there's a stone statue of an angel. Covering its eyes, as though weeping... except, when Mark