I've had to come to the defense of this season of Doctor Who on more than one occasion. The one-shot, autonomous, and heavily-themed episodes have been light-hearted (even by Doctor Who standards), and fun or dumb depending on who you ask. I've enjoyed them quite a bit so far, but even I have to admit that this week's episode was kind of weak.
The Power of Three tells the story of a time when the Doctor stayed with Amy and Rory off an on for a year—"The year of the slow invasion," as Amy calls it. One day, Earth is suddenly covered in mysterious black cubes, and the Doctor sticks around to figure out what they are. Eventually everyone gives up on figuring them out and the cubes become a part of every day life. It's an interesting premise for a Who episode for sure, but the way it's presented and the reason for the cubes leaves a lot to be desired.
Written by Chris Chibnall, the episode has a similar feel to his Pond Life series of mini-episodes that were released before this season's premiere. I don't consider this good news either, as the Pond Life shorts felt a lot like advertisements for the upcoming season premiere rather than actual Doctor Who tales. This episode isn't quite so bad but it has an uncharacteristically commercial feel to it. From the weird montage and voice-over at the beginning, to the overly clean look and The Doctor playing Wii, this episode felt like Doctor Who put through a focus-testing meat grinder.
One of the best parts of the episode is the way the mysterious cubes become a part of everyday life. With millions of them all over the world, people take to using them as decorations, paper weights, and more. There's even a reality show based around the cubes. This mystery and the fact that it all takes place on Earth gave the episode the feel of earlier seasons of Doctor Who. Amy and Rory, presumably as a result of better production values, haven't spent nearly as much time on modern-day Earth as we did with Rose, Martha, and Donna. Still, when the cubes turn evil and we find out the plot behind it all, the mystery of the cubes deflates into something far less interesting.
It turns out that the cubes are a sort of pest control that induce cardiac arrest in a third of the Earth's population, including one of the Doctor's hearts. The Shakri, the alien exterminator parked above Earth, conveniently keeps a portal to his ship in Rory's hospital. Using this, The Doctor, Amy, and Rory set about reversing the Shakri's plan and blah, blah, blah. The whole crisis is reversed and the Shakri's ship is destroyed. It all wraps up in a quick and convenient manner that completely diffuses the year-long invasion the episode is based around. But hey, sometimes you have to wrap up an episode and you only have five minutes.
Still, the episode is noteworthy for giving us some perspective on The Doctor's antics with Amy and Rory. While the two have been off on adventures for months at a time as far as their friends and family are concerned, they've actually traveled with The Doctor for ten years. If you've been following the Ponds through the last two seasons, that number probably seems pretty crazy.
Overall, this episode falls flat in delivering a compelling conflict, but succeeds in showing another side of Amy, Rory, and The Doctor. His companions have been killed, left behind, and more, but this is the first time he seems afraid to see them go. In the end, the two decide that their normal home lives can wait, and that there's no reason to stop adventuring. It'll be interesting to see if that ends up being their fatal mistake in the next episode.
Speaking of next week's episode, it's a mid-season finale of sorts. There won't be another one until the Christmas special. That said, it's also the farewell episode for Amy and Rory, directed by Steven Moffat, and features the Angels and River Song, so it's sure to be a big one.