Plot summary
Dr. Bashir and Chief O'Brien have spent the past week helping two races, the T'Lani and the Kellerun, dismantle deadly biological weapons known as "Harvesters". They assure the T'Lani and Kellerun ambassadors that all files related to the Harvesters have been destroyed, so as to prevent them from ever being created again.
When the moment comes to destroy the final Harvester, two Kellerun soldiers enter the laboratory and begin shooting the scientists, T'Lani and Kellerun alike. Bashir and O'Brien overpower the soldiers, but a drop of the Harvester liquid falls on O'Brien's skin. To escape, they are forced to beam down to the surface of the planet they are orbiting.
The T'Lani and Kellerun ambassadors inform Commander Sisko that O'Brien and Bashir died in an accident, and provide a recording purportedly showing the deaths of the entire science team due to an automated security routine. The senior staff of Deep Space Nine grieve the loss of their crewmates, and Sisko informs O'Brien's wife Keiko of his death.
Meanwhile, Bashir and O'Brien are stranded in an abandoned town on the planet's surface. O'Brien tries to repair a broken communications system in order to inform the T'Lani of the Kelleruns' apparent betrayal. Bashir discovers that O'Brien has been infected by the Harvester and, as O'Brien's condition begins to deteriorate, is forced to take over the repair effort.
Keiko insists that the recording of the supposed accident has been falsified: the video shows O'Brien drinking coffee in the afternoon, something she is certain he would never do. Sisko and Lt. Dax travel in a runabout vessel to visit the site of the "accident", where Dax investigates O'Brien and Bashir's runabout and finds evidence that its logs have been altered.
The T'Lani and Kellerun ambassadors show up together at Bashir and O'Brien's hideout. They reveal that the attack on the science team was a joint endeavor meant to erase all knowledge that could potentially be used to make Harvesters, and prepare to execute Bashir and O'Brien. Sisko and Dax rescue them by transporting them to their runabout. The T'Lani and Kellerun demand their return and fire upon the runabout when Sisko refuses; but Sisko deceives them by escaping safely in the other runabout.
As Chief O'Brien recovers from the Harvester poisoning back on Deep Space Nine, Keiko is stunned to discover that he does drink coffee in the afternoon.
Credits
Adapted from Wikipedia contributors, Armageddon Game. Paragraphs and formatting adjusted; illustrations, reference markers, block quotations and non-story material omitted.