This is an adaptation of HP Lovecraft's The Colour Out of Space. The Tenth Doctor and Celia find themselves in the mysterious forests around Boston, Massachusetts, battling an unseen foe that landed in a meteor in 1910.

This is an adaptation of HP Lovecraft's Shadow Out of Time. The Tenth Doctor and his new companion, Celia, encounter the Yith, an ancient alien race that inhabited the earth over 50 million years ago. They call themselves the Great Race, and the Doctor must find a way to stop their plans to take over the earth again.