"New Earth" is the first episode of the second series of the British science fiction television series Doctor Who, first broadcast on 15 April 2006. It is a sequel to the first series episode "The End of the World", and brings back its villain who was thought to be destroyed, Lady Cassandra, as well as the mysterious Face of Boe. In the year five billion and twenty-three, after the destruction of Earth in "The End of the World", the Doctor and Rose arrive on the New Earth and enter a hospital run by half-alien cat-like nuns called the Sisters of Plenitude, who have been hiding a gruesome secret.

The Doctor takes Rose to the farthest point he's ever taken her, to the year five billion and twenty-three in the M87 galaxy. After the destruction of the Earth, humanity settled onto a world they named "New Earth". The Doctor is summoned to Ward 26 in a hospital in New New York through his psychic paper. In the Ward, the Doctor meets several humanoid feline nuns of the Sisters of Plenitude who are overseeing the patients. The patients catch the attention of the Doctor because they all have incurable maladies but are somehow being cured by the Sisters. The Doctor recognises the Face of Boe, who sent the message the Doctor received. Meanwhile, Rose is separated from the Doctor and brought to the basement, where she is escorted by Chip to meet Lady Cassandra. Chip has been using the hospital facility to care for Cassandra, but she is suspicious of the methods used in the hospital and needs Rose's help to investigate. Rose is tricked into stepping into a psychograft, a machine that allows Cassandra to implant her mind into Rose's body possessing her. Examining her new appearance, Cassandra is initially disgusted by Rose's "Chav" outfit but soon decides she is attractive enough. She is able to access Rose's thoughts and learns of the Doctor's new form.

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