Frank and Clare travel to Moscow to deal with the serious political situation involving an imprisoned US activist.
For the duration of the episode we see Frank locked in negotiations with Pretrov and Claire trying to persuade Corrigan to read a statement prepared for him by the Russian government that denounces all his personal beliefs. Everything that happens during these exchanges are the build up to a pretty explosive ending. There is also a sub-plot involving the continued search for Rachel which is not quite as compelling.
I'm not sure why other reviewers reacted so badly to how the episode ends. Yes, I agree that these events are not particularly realistic, but at the same time this is a television show and is not meant to be taken so seriously. The entire tone of House of Cards is unbelievable when you consider how everything works out just right for Frank, no matter what seemingly insurmountable odds he is up against every season. However, the point of the events shown are to make overall narrative of the series dramatic and develop the central characters.
I think it ended well, in that it made me wonder if Clare's character will now develop differently to how she's been portrayed so far. Has it made her more ethical and less cynically ruthless? Maybe it hasn't. Perhaps she is just reacting to a new opportunity she can see in the circumstance as a means to undermine Frank and achieve more of her own power. It could be neither. Perhaps it's just a bump in the road designed to test their partnership and loyalty to each other.
Kevin Spacey and Robin Wright are absolutely scintillating during their character's eventual confrontation and the episode themes of strength, courage and loyalty come through with the venom they shoot at each other.
As always the production values are top notch in terms of cinematography, editing and in particular the musical score.