An unmanned spaceship hurtles towards certain destruction - unless the Doctor can save it, and its impossible cargo... of dinosaurs! By his side a ragtag gang of adventurers; a big game hunter, an Egyptian Queen and a surprised member of the Pond family. But little does the Doctor know there is someone else onboard who will stop at nothing to keep hold of his precious, prehistoric cargo.

The Doctor gets a Stetson (and a gun!), and finds himself the reluctant Sheriff of a Western town under siege by a relentless cyborg, who goes by the name of the Gunslinger. But who is he and what does he want? The answer seems to lie with the mysterious, Kahler-Jex, an alien doctor (yes another one!) whose initial appearance is hiding a dark secret.

Christmas Eve, 1892, and the falling snow is the stuff of fairy tales. When the fairytale becomes a nightmare and a chilling menace threatens Earth, an unorthodox young governess, Clara, calls on the Doctor for help. But the Doctor is in mourning, reclusive and determined not to engage in the problems of the universe. As old friends return, will the Doctor really abandon humankind, or will he fight to save the world and Christmas from the icy clutches of this mysterious menace?

Something ghastly is afoot in Victorian Yorkshire, as bodies are found with their skin a waxy, glowing red.

Someone is kidnapping the Doctor's friends, leading him towards the one place in all of time and space that he should never go.