This was a seven-part serial, first broadcast between 20th May - 1st July 1967. The serial was written by David Whitaker, produced by Innes Lloyd and directed by Derek Martinus. The script editors were Gerry Davis (for the first three episodes) and Peter Bryant (for the remaining episodes).
What I've seen:
Episode two. The other episodes are lost.
At the end of the previous serial, 'The faceless ones', the Tardis has been stolen. At the beginning of episode two, the only episode still in existence, the Doctor and Jamie are still searching for the Tardis and are lured into a trap by antiques dealer Edward Waterfield, whose daughter Victoria is being held hostage by the Daleks. They're forced to take part in an experiment that the Daleks are performing in order to find the human element - the one thing that has always defeated the Daleks in the past.
With only one of the original seven episodes still in existence, this is among the most incomplete of all incomplete serials. From this one episode it's hard to get an idea of the story as a whole, and yet it's oddly satisfying. It's well-directed, there are good performances from everyone, and even if you're not sure what exactly is going on you realise that you're watching something very good indeed.
Watching the one remaining episode made me want to hear the audio version of the entire serial.