Defending the Earth was the title given to a series of four specials which ran in 2010 set in Pete's world and starred David Tennant as the Metacrisis doctor along with Billie Piper resuming her role as Rose Tyler.The series takes place around the Torchwood One in that universe. In the final episode the TARDIS coral's growth is accelerated by use of alien vortex manipulation technology and the Doctor and Rose set off to begin their adventures in a new universe.
Episode One: Cyber shock
The planet Mondas returns to the solar system, many years after it did in the mainstream universe, and the Torchwood team must deal with Mondasian Cybermen.
Episode Two: Cracks
Torchwood's dimension manipulation technology catches up with them. The Doctor and Rose must use all the equipment available to prevent huge rifts from bringing through creatures from other planets.
Episode Three: Pendant
A strange alien amulet is found in the wreckage of a crashed spaceship which causes a child who wears it to become possesed by a strange psychic entity who then in turn infects other children. Using Torchwood systems the Doctor develops sound modulation software mimicking the sonic screwdriver, the sound made by this program can be transfered through a small speaker implanted in a thin tube. This tube would later be known as the sonic lockpick.
Episode Four: Departure
Using alien technology the doctor sends the fledgling TARDIS he is working on back in time and in a secret location to finish its growth process, he then begins augmenting the mechanical parts and "six months later" the Doctor and Rose depart in their fully completed TARDIS to begin journeying in a new universe. The episode ends with them arriving at Torchwood House and meeting Queen Victoria again, thus explaining the foundation of Torchwood in Pete's world.
The Doctor: David Tenant
Rose Tyler: Billie Piper
Jake: Andrew Hayden Smith
Jackie Tyler: Camille Coduri
Peter Tyler: Shaun Dingwall