Another memorable episode of the Martha Run. A returning villain (although perhaps villain is a stretch, threat maybe), a couple of high-profile guest stars and a return to New Earth.
Deciding to extend Martha's (Freema Agyman) stay to one more trip, The Doctor (David Tennant) takes her to New Earth and to New New York. Martha is kidnapped and taken on board a flying car on the underground motorway, where vehicles and their inhabitants have been trapped for decades. As the Doctor tries to rescue Martha, he's tracked by one of the cat nurses from his previous trip here but she has been sent by an old friend.
Fun as though this episode is, and with some memorable moments, there are elements that don't particularly make sense. One struck me whilst watching, the threat of the Macra only exists for people that come down to the Fast lane, but if the car flies at the top of that level, so as high as they can without entering the regular traffic again, the Macra would not be able to reach them. Admittedly, they're still trapped in an endless loop, but still, they would at least be safe.
Away from that it's a solid episode. Ardal O Hanlon appears in a fun cameo as Brannigan, pilot of the car that the Doctor first gets into and who explains the situation to him, and his cat make up really is exceptional work, even better than when we first met the cat characters back in the first season. Lenora Crichlow, post "Sugar Rush" but before "Being Human" also appears as one of Martha's kidnappers. The episode keeps up the idea that the Doctor is recreating his Rose experiences with Martha. Last time taking her to meet one of history's great authors, but this time more explicitly taking her to exactly the same planet and city that he took Rose too. She is naturally non-plussed when she discovers this. The Face of Boe reappears for the big "foreshadowing" moment that pays off at the end of the season and for what is the characters demise, but not the last time we'll see him.
It's fine, with strong moments and ideas, but flimsy and lacking in much logical depth.