Who shot the Watcher? Uatu, the mysterious space-god who's been watching mankind from the moon for as long as we can remember ... is dead. Thus begins the greatest murder mystery in Marvel history! As Nick Fury leads the heroes of the Marvel Universe in an investigation, other forces are marshaling and other questions are arising. Why is Black Panther gathering a secret team of his own, including Emma Frost, the Punisher and Dr. Strange? Who is the Unseen? What was stolen from the Watcher's lair? Fury's cosmic manhunt leads to the far corners of the universe and beyond, but just when the Avengers think they've cornered their murderer ... everything explodes, unleashing the Marvel Universe's greatest secrets and rocking the heroes to their core! What did the Watcher see? What was the Original Sin?