In this week's episode the Doctor, Amy and Rory are reunited five years in the future. Amy is heavily pregnant and Rory is sporting a hideous ponytail. And it might be best to avoid all the residents of the old folk's home.
And in this week's episode the Tardis looses power as it falls towards a "cold star" and the Doctor, Amy and Rory are reduced to wearing "Peruvian folk group" ponchos to keep warm.
Which one is real? It's important because, as Toby Jones says, if you die in a dream you wake up, whereas if you die in reality you, er, die.
Nothing Earth-shattering in this episode. The viewer knows at least one of the realities is fake so the sense of jeopardy is lessened. However the Doctor is forced to face his "friendships" with his companions and Amy is forced to realise how she feels about Rory.