Shining Shadows/The Clockwork Catastrophe

The Clockwork Catastrophe was the first regular episode of Shining Shadows. It introduced [name here] as companion.

Synopsis
The Doctor is traveling alone, and finds himself on the planet Antikythera in the 51st century. At first, this world of clockwork and steam seems quite inviting. But all is not as it seems: the citizens of Coldfire City worship a group of impossible enemies, an unseen mastermind is planting bombs throughout the landscape, and someone is trying to kill the Doctor...