The Doctor against an intelligent body snatcher cactus and some lame space pirates? The whole idea is so bonkers that you either love it or hate it. I myself belong to the first group. ( )

The people of Tigella are worried: the mysterious Dodecahedron that powers their entire civilization is having power fluctuations. They call upon the Doctor for help. Unbenknownst to them, the Dodecahedron many of them worship as a god was actually created by the plant people of Zolfa-Thuron. The Zolfa-Thurons destroyed themselves in civil war over the Dodecahedron, and only one survived: the malevolent Meglos! He traps the Doctor, Romana, and K-9 in a temporal loop, then shapeshifts to look like the Doctor and descends upon Tigella as their awaited savior. Naturally, the Doctor manages to escape, and after a few near-murders caused by looking identical to Meglos, foils Meglos's plan.

The story is nothing special, but I always love the Doctor's interactions with Romana. It's interesting that this is yet another story featuring alien humanoids who rely upon technology they don't understand. ( )

http://nhw.livejournal.com/1051656.html#cutid7

For once, Dicks has filled out a lot of background to what was otherwise a somewhat rootless story. The Earthling whose body Meglos borrows gets a name; we get the history of Zolfa-Thura in terms which very nearly make sense, and the whole thing is a definite improvement - though, alas, from a poor starting base. ( )