O'Brien is kept busy by the continual system breakdown around the station. While making repairs on the tricky food replicators that break down more often than not, he accidentally trips on a Bajoran device release an adaptive virus into the food generated by that replicator. O'Brien becomes immediately stricken with the disease, which scrambles the relaying efficiency of the brain synapses, rendering him incapable of connecting language, stimuli and responses.

Quark, meanwhile, is impatient to resume business at his bar and unwittingly spreads the virus to all his patrons, creating a station-wide epidemic. Bashir, of course, comes into the spotlight at this point, being the only man aboard who could save the station. Only a few, Odo, Kira, and Quark himself, are left unaffected, and he must procure an antidote before he himself falls victim. The virus was put in place by Bajorans years ago when they tried to sabatoge the construction of the Cardassian mining station and is eventually fatal. With very little time and the Station security nonexistent at that point, the four beat the odds and finally did bring back the comatose population.

Credits: Teleplay by Michael McGreevey and Naren Shankar Story by Sally Caves and Ira Steven Behr Directed by Paul Lynch Music by Dennis McCarthy