Decent enough episode. Like the Saul storyline, interesting to see if he flees and awaits what Carrie comes up with, but also how the inevitable Dar Adal reconciliation will work. Once it's clear that Alison is the main baddie, I suspect that all will be forgiven between Saul and Dar (and that Carrie will also find her way back to the CIA).
The Alison back story was also good, it gave a good account of how she got to be a SVR asset. Her personal relationship with Acrobat was plausible (in the Homeland world anyway).
Quinn's storyline is also intriguing, didn't see the plot change for the terrorists to go back to Berlin coming. I had expected them to go to Syria and try to kill the emir and his cronies there. We'll probably see more AS/German cooperation in the next few eps to avoid Berlin/Germany getting hit, and for the two security agencies to become BFFs again by exposing Russia.
Did think that it was a bit transparent for Carrie to put the pieces together as a result of seeing a screensaver, but hey, it's all nicely set up for the next few eps.