Holed up in the police station with the few survivors, the marines hot-wire a bus and make their getaway. Along the way they learn a few things about the aliens - that the weak spot is to the right of their heart, and that these guys love water.
The bus is attacked by a drone ship - and is taken out by the brave Nantz, acting as a Lone Ranger.
They come to a stop on a bridge when a ramp to join the freeway has been obliterated. The aliens attack again, and have a robot cannon to keep the good guys pinned down. The marines take their sweet time to get a few kids on abseil ropes to the lower level, while one of the survivors, Hector, is hit protecting the others.
To help them get away, Martinez (the guy in charge, who has been badly injured) sets an explosive charge as the aliens approach to give them some time.
Those who are left get into a supermarket and wait for the bombs to drop.
Rather than give it a few minutes to be on the safe side they guess that the airforce must have been wiped out. They leave the safety of the supermarket and venture out to the FOB (Forward Operations Base) to find that it has been hit. Hector dies at the base.
The marines left get into two Humvees and make a run for the next evac point. They mow over a few alien stragglers, and make it to a waiting chopper.
They fly over an area of interference. Nantz knows he still has a job to do, and rappels to the ground. The other brave marines join him.
They follow a few alien sentries underground and find the submerged giant command center. They launch an RPG at it, but it is still standing. Suddenly the drones tie a few ropes around the frame and start to haul it away. Nantz calls in a strike and 3 missiles are on their way -- but the aliens send drones out to take the first two missile hits.
With the last RPG, Santos (Michelle Rodriguez) makes herself useful and takes out the drone, allowing the tomahawk to strike the command center and send it back to earth in flames. All the drones fall from the sky, and the confused aliens make a run for it.
Nantz and his crew get a lift out to the Mojave Desert and inform the Commander of their success, and the news is relayed around the world Independence Day style. They are congratulated and expected to enjoy a well earned rest ... but Nantz isn't finished. Or hungry. He reloads his weapons. The other join him, and before long they're ready to go back out again, to the amazement of the desk jockey chief.