Who killed the Watcher? Uatu, the mysterious space-god who observes mankind from the moon, is dead. Thus begins the greatest murder mystery in Marvel history! As Nick Fury leads a cosmic manhunt to the far corners of the universe, other forces marshal and other questions arise. Who is the Unseen? What was stolen from the Watcher’s lair? 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? As all the truths come tumbling into the light, discover the Original Sins of dozens of major characters, from the Inhumans to Dr. Doom to J. Jonah Jameson!