For months, the FBI have been on the hunt for a terrorist who seems invincible. The death toll is rising, yet somehow the killer, known only as the "Green man", has avoided leaving a single clue. But this is no ordinary villain. Each attack is carefully planned to destroy a target that threatens the environment. Each time, the protest movement that supports the Green man grows ever larger. Tom Smith is a young computer programmer with the FBI, trying to escape his father's domineering shadow. An expert in pattern recognition, Tom believes he's spotted something everyone else has missed. At long last, Tom makes a breakthrough. But as he closes in on America's most dangerous man, he's forced to ask himself one question: What if the man you're trying to stop is the one who's trying to save the world?