Doctor Who: The Quantum Possibility Engine

Although technically this is the third part of a trilogy, in that the previous two instalments both ended with teasers for the one that followed, this is very different in tone to either of its predecessors. In fact, it's a comedy, something that's not often done with Seven. The comedy elements don't overwhelm the plot, however, and don't fall into the trap of seeming overly silly, which can sometimes happen when you insert a comedy episode into something that's normally serious.

The plot sees the TARDIS captured by the story's main villain, Josiah W. Dogbolter, a character created for the DW comics of the 1980s. That occurs during the teaser at the end of the previous release, and this story is concerned not so much with getting it back as with what Dogbolter plans on doing with it. The usual companions are joined by Narvin, from the Gallifrey audios, whose frustration with what is going on helps him to serve as a comic foil.

Time technology is involved in the story, as one might expect, but it's nothing particularly complex with no paradoxes or out-of-sequence events. In many respects, it's quite serious, with the humour being provided by some of the characters - an obsequious protocol droid, image-conscious alien invaders, etc. - and a number of good one-liners. Despite the larger cast, all of the characters get something to do, and there's a nice piece of implied commentary on the relevant era of the TV show when it becomes clear, early on, what Mel is really doing...