This story has been hailed by many as the best traditional sci-fi episode. Personally I like it because it introduces Elizabeth to us. It also has that moody, psychedelic, quality which sums up the seventies so well. I was rather disappointed the ending though. How could they manage to build giant stun guns in space in so little time, even with their super powers?

There would also have been many deaths caused by people falling asleep whilst driving, working machinery, etc. I believe that this was not explored enough and the prime barrier was overcome too easily.

Although this is an early episode, the common theme of the stupidity of the police force seems obvious. Despite Stephen's efforts to wipe the memories of those officers involved in Chris' arrest; didn't anyone think it odd that they suddenly awoke to find themselves lying in the middle of the street? I wonder whether Roger Price wanted to make some personal point about the police throughout the series.

The worst part of the whole story is PVC's poor acting, but of course I was far too infatuated by his boyish good looks to notice at the time.