Plot summary
An archeological dig on Bajor reveals an ancient tablet in an ancient Bajoran language that addresses the Emissary. Sisko brings the tablet to Deep Space Nine for further study, raising the ire of Kai Winn, who protests not being consulted in advance, and resents Sisko's connection with the Prophets. Dax 's analysis of the tablet reveals an upcoming event called the "Reckoning", possibly involving the destruction of the station, and during which Bajor will experience great suffering. Meanwhile, the wormhole begins to behave erratically, causing disturbances on both the station and the planet.
Winn attributes this to Sisko's possession of the tablet and forces him to agree to return it to the planet in the morning. That night, however, Sisko becomes frustrated at the Prophets and smashes the tablet, which releases red and blue vapors that dissipate into the station. Kai Winn is furious, but Sisko states his belief that he is doing the Prophets' will.
The station begins to experience mysterious power fluctuations, and the crew soon discover that Major Kira has become possessed by the blue mist – a Prophet – which is exuding intense power. The Prophet reveals that it is waiting for a Pah Wraith to battle it in the Reckoning. Most of the senior staff strongly recommend flooding the Promenade with radiation that would force the being to leave Kira, but Sisko refuses to interfere with the Prophets, and Odo states that he believes Kira is a willing participant. Sisko evacuates the station, but Kai Winn stays behind to witness the conflict, as Bajoran prophecies indicate that the Prophet's victory in the battle will result in a golden age for Bajor.
The Pah Wraith appears, having taken over the body of Sisko's son Jake, and it and the Prophet begin to battle, creating a dangerous energy buildup. Sisko orders the last of the crew to evacuate, but refuses to leave his son behind, believing the Prophets will not allow him to be killed. With the Prophet appearing to have the advantage, but both adversaries showing wounds from the struggle, Winn executes the command to flood the Promenade with radiation, interrupting the conflict and forcing both beings to leave. After her recovery, Kira accuses Winn of intervening out of jealousy over Sisko's greater faith, and warns her she will have to answer for the consequences of her actions.
Credits
Adapted from Wikipedia contributors, The Reckoning (Star Trek: Deep Space Nine). Paragraphs and formatting adjusted; illustrations, reference markers, block quotations and non-story material omitted.