About the same writing quality as the Jade Pyramid (Which it came with as a set, and which I've already reviewed here, which is why I didn't put up the same cover twice.) but not read by Matt Smith. The Doctor's dialog still doesn't sound like the Doctor, but perhaps a little closer. This one is more like a regular episode of the series, something like the David Tennant episode Waters of Mars, where an alien intelligence is taking over people's bodies and turning them into zombie like monsters. There is one cool bit. Whenever the aliens talk through their human hosts, their voices have been made to distort and echo slightly. A nice use of the fact that this is an audio adventure. There are also some good sound effects for space cruisers, ray guns, the Tardis, and so forth. I enjoy these audio books that are sort of like Radio shows too.
There's one cute dialog exchange where a character asks the Doctor how he knows how to fly a space cruiser and he says something like, "I'm used to piloting a far more complicated ship that's designed to be flown by six people all by myself. I think I can handle this."