“In Purgatory’s Shadow” is episode fourteen of season five of Star Trek: Deep Space Nine.
This episode opens with Odo and Major Kira modifying the former’s quarters, as he once again is a Changeling following the events of “The Begotten”, when an encrypted Cardassian message is received from the Gamma Quadrant. Garak states that the message is simply a planetary survey, but Dr. Bashir thinks he’s lying – and he is.
The message is actually from Garak’s former mentor, and the former head of the Obsidian Order, Enabran Tain, who was lost in “The Die is Cast”. Garak wants to head into the Gamma Quadrant to look for him, and any other survivors from the Romulans, Bajor and the Federation. Sisko decides to allow him to take a runabout through the wormhole, along with Worf.
They are taken captive when they stumble on a vast Jem’Hadar fleet close to the wormhole – a fleet large enough that the Dominion must be planning an attack. They are taken to an internment camp, where they find Tain, and General Martok, who was discovered to have been replaced by a Changeling in “Apocalypse Rising”. There’s someone else there too, meaning another Changeling is loose in a sensitive place. Garak has a final meeting with Tain, and something new is revealed about their relationship.
Gul Dukat is on the station having ship repaired, and he really disapproves of Garak’s relationship with his daughter. There is also a reference to the events of Star Trek: First Contact.
The events continue in the next episode, “By Inferno’s Light”.