Its the episodes sole focus, and for good reason.
At the outset of the episode, war isnt on the horizon.
Nuclear disaster is barely avoided.

Credit: Liane Hentscher
Juliana gives him the film, and before she has time to get back inside, hes vanished.
Things arent so cool and calm back in the world controlled by the Nazis and Japanese.
He rushes upstairs with Juliana, only to be held at gunpoint by George.
Thus, the Resistances big plan is underway.
He barely gets those words out before hes shot dead as Juliana watches in horror.
Now he has no choice but to go on the air and confirm that Hitler is indeed dead.
Gary brings Frank in to discuss the plan for the bomb.
Gary says hell do the job himself, but Frank wants to take it on.
Take the meeting between Thomas and Juliana for instance.
Its an adorable flashback that shows the strength of the trio, that their friendship is something special.
The sentimentality would be nice if it was given room to breathe.
The rest of the episode flies through plot points.
Shots are fired before the bomb explodes, but well have to wait for the aftermath.
Its one more mysteryThe Man in the High Castlemight have no interest in explaining anytime soon.