Series 4 - Episode 5: The Poison Sky

Written By:
Helen Raynor

Original Air Date:

2nd May 2008

Synopsis:

The 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?

Monster/Villain:
Sontarans, Luke Rattigan, Martha's clone, U.N.I.T. soldiers (hypnotised)

Location:

London, Earth (2009)

Tenth Sontaran Battleship (2009)

Videos:
Clip - Rose


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