Fantastic Four #536
The Hammer Falls: Part 1
A small object was detected approaching North American airspace before crash-landing in a relatively empty stretch of Oklahoma.
Six months later, Reed Richards returns from his meeting with the Illuminati and catches a report on CNN concerning Tony Stark's testimony before Congress regarding the Superhuman Registration Act. Sue questions whether the government would really seek to force superheroes to register, but the conversation is interrupted by General William Ray, who seeks the Fantastic Four's help.
In Oklahoma, a perimeter and a research installation have been established around the fallen object, while the military attempts to repel a battalion of Doombots. The Fantastic Four soon arrive and relieve the military in the skirmish; while Sue, Grimm, and Johnny battle against the Doombots, Reed meets with the field commander and learns that the military's major radar and battlefield imagining systems have been knocked out. Moments later, missiles rain down on the installation and destroy the dome, after which Victor von Doom arrives, revealing that the object which fell to Earth six months prior was in fact Thor's hammer, Mjolnir.
Recurring Characters
Fantastic Four (Mister Fantastic, Invisible Woman, Human Torch, Thing), Doctor Doom
Continuity Notes
At the time of this story, Thor was seemingly slain in Thor Vol 2 #85. He eventually returns from the dead in Thor Vol 3 #1.
The flashback scene with the Illuminati takes place in New Avengers: Illuminati #1.
The news clip of Tony Stark talking about super-hero registration is expanded upon Amazing Spider-Man #530.
The reason why Reed is shocked to see Doctor Doom is that the last time Reed saw Doom, in Fantastic Four #507, Doom was trapped in Hell.