As with all old Doctor Who, you take the bad with the good. The story is quite simplistic, and borders on ridiculous on several occasions. Episode one is brilliantly done, and my respect for it only grew after learning that they had to add it to this serial at the last minute with no budget at all.

The production also had the problem of one of the main characters contracting chicken pox during filming and needing replaced for an episode. Their solution would never have worked on any other serial!

Overall, the story is slightly silly, and the monsters aren't particularly scary – but there's a great variety of them, at least. Patrick Troughton does a great job, and his performance almost (but not quite) saves the story. There are far better second Doctor stories out there (like the Invasion, or Seeds of Death). Overall though, the 6-year-old in me couldn't help but enjoy it anyway.

Also, there are really good special features on this disc. The making of documentary is pretty good. Add to that, I've always had a soft spot for Basil Brush, and he appears with a different Troughton-era foe in a brief skit.

Go in with lowered expectations and you'll be fine.