Archer and Trip visit an alien colony seeking deuterium fuel, but their suspicions are aroused when the planet's drillers prove reluctant to deal with them. Aboard Enterprise, Mayweather's sensors detect an approaching Klingon vessel.

Returning from covertly observing a preatomic-era alien world on the verge of war, Lieutenant Reed realizes he lost his communicator somewhere on the planet. Archer and Reed return to recover the lost technology, only to find the natives found it first. Captured and interrogated as spies, Archer and Reed find themselves doing even more damage to the culture when they are scanned and found to belong to another race. They face execution and autopsy. Meanwhile, Tucker and Mayweather try to figure out how to activate the cloak on the Suliban cell ship so they can mount a discreet rescue.