This one has grown on me over the years. The mystery of what's going on makes episodes 1 and 2 good. Episode 3 is a bit slow, but then it picks up again in ep4. We get to see Harry and Benton again, but this,sadly, is the last appearance for both characters. Having androids is fun as we don't know if it's the actual Doctor, Sarah, Unit soldiers...etc, or if its an android. The Kraals are fine as the alien villains. Overall, this story is better than you remember.