The Poison Sky is the fifth episode of the fourth series of British
science fiction television series Doctor Who. It was broadcast on BBC
One on 3 May 2008. The episode features both former companion Martha
Jones and the alien Sontarans. It is the second of a two-part story;
the first part, "The Sontaran Stratagem", was broadcast on 26
April.Continuing from the previous episode, "The Poison Sky" reveals
the poisonous gas that is choking the Earth's atmosphere is intended
as a way of feeding new batches of Sontaran clones that would be bred
on Earth for war.400 million cars on Earth equipped with ATMOS devices
are suffocating humanity with poisonous gas. Sylvia frees Wilfred from
her car by breaking the windscreen. The Tenth Doctor tells Donna's
family to get inside and seal the windows and doors as best they can.
He and Donna return to the ATMOS factory, where the Doctor warns UNIT
not to engage the Sontarans. The Doctor tells Donna to stay in the
TARDIS for her own safety, but the Sontarans locate and teleport the
TARDIS aboard their ship. The Poison Sky Biography, NetWorth, Height, Age, Weight, Family, Married, Son, Daughter