The Doctor is stunned when Donna Noble suddenly appears in the TARDIS. He has no idea how she got there and she wants to return to exactly where she was when she vanished - walking down the aisle of the church and about to be married. A quick return to Earth and a check into her background reveals that her company was once owned by the now defunct Torchwood Institute. The Doctor finds that Torchwood had built secret facilities under the Thames barrier where he also finds the cause of the problem: the Empress of Racnoss, a spider-like creature who is trying to re-establish her kind. The Doctor and Donna will have to travel billions of years back in time to the very formation of the Earth to understand what she is up to.
—garykmcd