I didn't need to hear her name was Kate Stewart to know she was the daughter of Brigadier Lethbridge-Stewart--actress Jemma Redgrave looks so much like him I was surprised she wasn't related to Nicholas Courtney. In any case, I love the tribute paid to the Brigadier by her presence in "The Power of Three", to-day's Doctor Who episode, though it was otherwise a pretty lightweight episode. The invasion of Earth by black cubes felt very Russell T. Davies, which was emphasised by cuts to people in various locations in the world and news broadcasts, and it served to show how formulaic those episodes had become. Though I liked the subtle metaphor in the cubes for iPhones.
I think it was also greyed out a bit by the focus on the Ponds choosing between regular Earthly life and life with the Doctor--that plot and the invasion plot suffer from having to sit with each other, and neither finds footing, though the invasion plot suffers more as it feels a lot like just an excuse for the other stuff.
The weakest episode of the season so far. I can't believe there's only one more until there's none 'til Christmas. Amy looked really cute, though.