Separated from the TARDIS and Amy Pond, the Doctor faces his greatest challenge yet: pass as a normal human being, with no technology to help him figure out the mystery of what's going on in 79A, Aickman Road. To do so, he must become "The Lodger", the eleventh episode of the 2010 series of Doctor Who. It's a fun little adventure and a surprisingly good breather between a stream of high-drama stories.

As the TARDIS is stuck in a materialization loop with Amy trapped inside, the Doctor becomes the flatmate of one Craig Owens (James Corden), who pines after his colleague Sophie (Daisy Haggard) while otherwise content with his unremarkable life - planning meetings at work, football with his friends and pizza-booze-movie nights with Sophie. But while Craig works up the nerve to tell Sophie he loves her, people passing by his house are lured to the upstairs room, where the lights flash and the door closes on their screams. Convinced that whatever is happening in 79A is responsible for the TARDIS being unable to materialize, the Doctor tries to get to the bottom of the mystery, unintentionally turning Craig's simple life upside-down in the process.

Sandwiched between a high-profile run of episodes (the return of the Silurians and Rory's death/erasure in "The Hungry Earth"/"Cold Blood", the van Gogh masterpiece "Vincent and the Doctor" and the final episodes of the season), "The Lodger" holds its own innocuously well. Matt Smith shows off his comic chops, headbutting a frantic Craig, playing football, kissing everyone on both cheeks and talking to a cat. Corden and Haggard are engaging, if unextraordinary, as the "will they, won't they, why won't they, here we go again" couple.

The episode veers dangerously close to Doctor Who's version of romantic comedy: Sophie is obviously settling for second-best with Craig; she thinks the Doctor is "gorgeous"; obliviously invites him to join her and Craig for what Craig had planned to be a romantic evening; and cheers the Doctor on at a football game, before belatedly assuring an out-maneuvered Craig, "You're brilliant, you're amazing". Craig finally declares his love for her, providing the episode with its resolution (amidst showers of sparks and the Doctor yelling "For God's sake, kiss the girl!"), and it's a rare relief to see a young woman in the Doctor Who revival be happy with the man she has chosen.

For all the comedy in the episode, the science fiction doesn't quite work. The Doctor's home-made scanner is a laugh, but the Time Engine leaves a lot to be desired. The ship is just looking for a suitable pilot - why make us think it was something malevolent, luring innocent people to their deaths up a dimly-lit staircase? What actually happens to the Time Engine? Is it destroyed? There are lots of little moments in "The Lodger" that might yet prove significant in the last two episodes of the season, but the episode works a lot better if you remember the lighter moments over when it tried to be serious.

It's hard to pick one single best scene of "The Lodger", because there are so many good ones. Of them, the Doctor handing Craig a paper bag with £3,000 in cash and saying "Have some rent" is particularly inspired. Amy picking up the engagement ring given to her by a man who doesn't exist anymore sets things up quite nicely for the finale, leaving "The Lodger" at 4.0/5 - pleasant, comfortable and more entertaining than you'd think.