With the Doctor, Rose, and MP Harriet Jones trapped inside Downing Street, the Slitheen make their move: Nuclear Warfare. If the human race is obliterated, the Earth can be sold on the Galactic Black Market for a very reasonable price. It's up to the Doctor to defeat the Slitheen before the entire population of the Earth is wiped out. But will he have to make the ultimate sacrifice: Rose Tyler... ?
The Doctor has returned! Travelling through time and space in his TARDIS, the Doctor battles aliens and monsters who are intent on mayhem and destruction.
He is joined on his adventures by a number of companions: Rose Tyler, an East London girl looking for a way out of her boring job; Captain Jack Harkness, a time traveller and conman from the 51st century; Donna Noble, who is sucked into the TARDIS on her wedding day, and is now looking for the dangerous life the Doctor leads; and Martha Jones, a 23 year old medical student, who is whisked into the Doctor's life when the hospital she works in is transported to the moon, she leaves the Doctor after saving the world from the Master because she knows her love for him isn't reciprocated. Soon after when the Earth is threatened with alien invasion Donna returns to the Doctor to help save the planet.
After facing down the Time Lords of Gallifrey and averting the End of Time, the Doctor regenerates and meets young Amy Pond, as a young girl and is reunited with as an adult, along with her fiance Rory. Together, the three traversed time and space continuing the fight against evil... that is, until the Ponds leave. The Doctor begins traveling with a woman twice dead, Clara Oswin Oswald, and continues his never-ending crusade. Finally, he succeeds in preserving Gallifrey in a pocket universe and is given a whole new set of lives by his people.