We hear often about how the nation is preparing for another attack, like 9-11, but it's very rare we get to see that in action. With nothing but a hand held camera, I hopped on a plane with the commander of U.S. Northern Command and experienced an exercise that felt more like real-life.

A simulated nuclear bomb goes off in Indiana and rescue crews search for victims in the rubble. More than 12,000 are dead and 14,000 are injured. In Colorado Springs, NORTHCOM jumps into action. Its job is to support the emergency operation in every way necessary. "City, county state responders immediately responded. FEMA was not far belong, but because of all the casualties and the damage, they’re overwhelmed, so DOD is asked for help," says Capt. Michael Collins, a participant in the exercise.

I hop on a plane with the commander of NORTHCOM, General Gene Renuart and his staff immediately to travel to Camp Atterbury, Indiana, the command post for this exercise. There, the general is briefed on what the National Guard and active military are doing in the town that was hit by a bomb.

By black hawk, we travel 20 minutes south to Muscatatuck, Indiana where General Renuart will see the damage first-hand. On the ground, he meets with Indiana's Lt. Governor Becky Skillman, who's already activated National Guard troops to help out. "We can't be prepared if we don't practice," says Lt. Gov. Skillman.

The general sees the efforts underway to find those still buried. The survivors are taken away to get medical help. Others, like the 65,000 exposed to radiation, are taken to get decontaminated. The soldiers cut off the woman's clothes. "Clothes are contaminated and so to get rid of all the contamination, the clothes have to go," says a soldier. The victim is then whisked away to doctors who care for her broken leg.

"We are a robust nation at all levels," says LTG H. Steven Blum, the National Guard Chief. The exercise is meant to stress the 3,000 first responders and military personnel to their limits. “The reality is there are forces out there that want to do us harm and we need to be prepared to respond," Gen. Renuart says.

This was the largest, most complex exercise put on by USNORTHCOM.