Doctor Who: Out of Time

Obviously, the pull of this is that it features a meeting between the Fourth and Tenth Doctors. It's set at points within both their timelines at which they are canonically travelling without companions which helps to keep things simple (as well as saving on the cast, one imagines).

The story itself is not particularly remarkable. There's a cathedral somehow opening doors onto different points in time and space, and the Daleks want to take it over to help in their war effort (the one from Planet of the Daleks, not the Time War). There's a lot of running about, people getting exterminated, Daleks shouting and, yeah, a minor subplot about a military deserter, but it's hard to say that there's anything special about it. The drama does build as it goes along, with a decent finale and it fits neatly into its one-hour timeslot although the beginning does feel as if you've stumbled in on the middle of something else because of the need to set things up quickly.

But.

The main reason people are likely to want to buy this is because of the pairing of two of the most popular Doctors of the classic and modern eras. In that respect, they will not be disappointed. There is some great dialogue and interplay between the two, contrasting the points on which they differ and emphasising where they are the same. This easily makes up for the routine nature of the plot and makes this great fun to listen to if you're familiar with both incarnations.