After such emphasis on the Doctor dropping in and out of Amy and Rory’s lives in Series 7 so far, this episode does feel like an inevitable one.

Remember The God Complex, where the Doctor gifted Rory and Amy a car and a house, and told them that he had to leave them while they were ‘still breathing’ and that the ‘bigger, scarier adventure’ was a married life without him? You do? Because the Doctor doesn’t seem to…

The Power of Three shows he just can’t relinquish the Ponds. And they can’t quit him. It was cute and vaguely diverting when we were presented with it in the form of the Pond Life webisodes, but sadly when stretched to a full 45 mins, it feels like a rehash of old ground and a wasted opportunity for a far more interesting alien invasion premise.

Millions of little black cubes appear overnight and then proceed to… do nothing. What are they? Who sent them? Why? It’s a great story concept, a plot that almost has the cordite whiff of Torchwood in its set-up; you can imagine Capt. Jack & Co. swishing in and picking up a few cubes to take back to The Hub for scans and innuendo.

Sadly the not-knowing is the best part. If you’re going to have a good mystery then you’d better have a good pay-off. The episode formerly known as ‘Cubed‘ does not. It’s rushed, confusing, and – even for a show where a man once fell in love with a paving stone – stretching the limits of human credulity. You have been warned.

The sci-fi is but a sideshow in an episode that mostly focuses on what it’s like for the Ponds when there isn’t danger and lasers and a Murray Gold fanfare turning your speakers to a gelatinous wreck. Yet after two series we know all we need to know about them. Nothing new is offered to their characters here. We don’t want to see Amy and Rory in their interstitial lives in an outrageously lovely house. Companions are made to run, not be caged in suburbia.

It’s not the only problem present. You should always worry when there’s more than one pop-culture reference in an episode of Doctor Who, and The Power of Three has a Tumblr full. There’s a reason why Tom Baker wasn’t making jokes about Crackerjack or George & Mildred while fighting mummies and spaghetti-faced art forgers: time is not kind. It’s why people snigger when James Bond criticizes The Beatles in Goldfinger.

The Angels Take Manhattan is going to be the Ponds’ last shout, so this is the intake of breath before it. But in such a short run there’s no room for such breathing space. Lacking the scope, rambunctiousness, and filmic quality of the previous three episodes, The Power of Three comes across as a messy version of an RTD era late-series filler-episode.

It’s a bold attempt at viewing the roles of the characters from a different angle, but it’s one that comes too late in the lives of Amy and Rory. We’ve met them, we know them, and dare we say it, we’re now very ready to say goodbye to them.

Airs at 7.30pm on Saturday 22nd September 2012 on BBC One.

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