4. The Land Of Doppelgängers
The Doctor is no stranger to doppelgängers, having recently been up close and personal with some rather unnatural creations of The Flesh. But what if the TARDIS took him on a wrong turn to a land filled entirely with exact doubles of himself? Or even worse, doubles of his companion? The Doctor has had a few close calls with nearly losing companions in the past, and this setting would certainly give new weight to the phrase, "don't wander off!". It would be interesting to see the Doctor's panicked reaction in this world, and it would definitely be a great way to re-visit the popular idea of The Flesh.