“You Don’t Know Jack” is episode sixteen of season three of Eureka.
Tess is creating a time capsule for the town using recordings of peoples’ memories, which means that a lot of this episode consists of flashbacks to previous episodes. Allison is not far off from having her child and the Global Dynamics facility is being emptied for its annual sonic clean.
Fargo, not wanting so many recordings of him to be about all the disasters he has caused, decides to delete the memories that show him in a bad light. Which is almost all of them. Being Fargo, this causes another disaster, as people start to forget things.
Carter and Allison end up trapped in Section 5 with the sonic cleaning about to begin, which will be fatal, and those that might help them have forgotten. Then Allison’s memories start fading too.