Hunger is rampant on Bajor until a replicator mysteriously appears, making food abundant. But Bajor's seeming good fortune takes a tragic turn when a new deadly disease begins to spread. The Provisional Government comes to the Federation for help, and Commander Sisko dispatches the Deep Space Nine crew to find the source of the tainted replicator and a cure for the disease. But while the disease quickly spreads across the planet, Sisko and Major Kira - with the aid of some unlikely sources - find themselves deeper and deeper in the underground maze of the blackmarket, with no apparent clues. When people on the station become infected as well, Doctor Bashir must find a cure to this disease, which now threatens to destroy not just Bajor, but the safety of the entire Federation!