“I’ll Be Seeing You” is episode nine of season four of Eureka.
This episode opens back in the past with Grant plotting to help stop the creation of the atom bomb by using the bridge device.
In the previous episode, “The Ex-Files”, it turned out that Beverley hadn’t wanted to destroy the DED – she wanted to steal it. Not to use it or resell it as a weapon, but for its power source. Carter and Allison had finally gotten together.
This will be used to power the bridge device so that Grant can travel back into the past. They are operating from a hidden (as in invisible!) building in Eureka. Henry and Allison are near the building when the device is activated, and the ensuing energy pulse hits their car causing it to crash, killing Allison.
Carter, arriving too late on the scene, breaks into the building and attacks Grant. Which results in them both being sent back to 1947.
When Grant find out that Allison is dead, he also wants to save her (as he, too, has feelings for her), so they end up running through the events of “Founder’s Day” from a different perspective. This could be considered as an entirely new take on the flashback episode.