The TARDIS brings the Tenth Doctor and Martha to Balmoral in 1902. Here they meet Captain Harry Carruthers — friend of the new king, Edward VII. Together they head for the castle to see the king — only to find that Balmoral Castle is gone, leaving just a hole in the ground. The Doctor realises it it the work of the Judoon — a race of ruthless space police. While Martha and Carruthers seek answers in London, the Doctor finds himself in what should be the most deserted place on Earth — and he is not alone.