The episode opened with CSI being called out to a crime scene, only there was no body. They found dozens of shell casing and blood but no victim or suspect.
When the shell casing turns out to match that of a military crime over seas the FBI comes in to assist. Catherine is teamed up with Agent McQuad and D.B. teams up with the younger Agent Pratt.
Catherine and McQuad eventually find the body and found that it had been cut in half by using the machine gun that killed the man, McQuad referred to it as “Zippered”.
The gun turned up a day later when a young man tried to use it to rob a store and lost control of it. Pratt told D.B. that there could be dozens more from the theft if they don’t find the rest. Hodges found a thread in the gun that pointed to the guns being shipped with rugs.
Sarah was able to recover the tattoo of the victim that had been cut up and using the information from it and the military stats they tracked the suspect to a local man who does shipment hauling in trucks.
Catherine and McQuad find the truck but when the climb in the back they are shot at, Catherine shot back and hit one of the shooters, the police showed up and killed the other. The guns got off the street and the killer was arrested but made a deal with the FBI for information he knew.