Original Air Date:
2nd May 2008The Valiant clears the ATMOS gas as the Sontarans activate their master plan to turn Earth into their cloning planet. UNIT is left defenceless, with a traitor in their ranks. And as interplanetary war edges closer, the Doctor has to fight to keep both Martha and Donna alive - but will he have to make the ultimate sacrifice?
Sontarans, Luke Rattigan, Martha's clone, U.N.I.T. soldiers (hypnotised)
London, Earth (2009)
Tenth Sontaran Battleship (2009)
Clip - Rose
Next Time Trailer