The Doctor (Christopher Eccleston) uses the extrapolator on the TARDIS to generate a protective shield as he materialises the TARDIS around Rose (Billie Piper) to rescue her from the Daleks. It seems the Dalek Emperor survived the Time War and escaped to Earth on a damaged ship, where he rebuilt the Dalek race by harvesting DNA from humanity. Returning to Satellite Five, Captain Jack (John Barrowman) uses the extrapolator to shield the top six floors of the station. The Doctor contemplates a delta wave generator which will destroy the Daleks, but also all life on Earth. The Doctor tricks Rose into entering the TARDIS and uses the sonic screwdriver to direct it to her home time to keep her safe. The Daleks invade the station, killing everyone they see.
Back at home, Rose notices the words Bad Wolf everywhere and realises it is a message for her. She enlists her boyfriend Mickey (Noel Clarke) and her Mum Jackie (Camile Coduri) to open the heart of the TARDIS with a borrowed tow-truck and Rose is bathed in the light of the Vortex. The doors slam in Mickey’s and Jackie’s faces and the TARDIS dematerialises. The Daleks reach the top of Satellite Five and exterminate Lynda and Jack. They file into the control room as the Doctor realizes he cannot extinguish the human race just to destroy the Daleks. Suddenly, Rose arrives in the TARDIS. Wrapped in the glow of the Time Vortex, she declares she is Bad Wolf and disintegrates the entire Dalek fleet.
The Doctor begs her to relinquish her new power, but instead she resurrects Jack. She begins to collapse under the strain. The Doctor kisses her, absorbing the power of the Vortex into his own body, saving her life. He releases the power back into the TARDIS and carries her, unconscious, back inside. They depart in the TARDIS, leaving Jack behind. The Doctor dies and regenerates as the Tenth Doctor, David Tennant.
An alternate ending was filmed to show the Press, keeping secret the regeneration, and implying that Rose died. David Tennant’s appearance was filmed later. The BBC said Eccleston quit because he was afraid of being typecast but had to apologise later because that wasn’t true. Actually, he said he could not get along with some senior people, which I think meant writer and producer Russell T. Davies. Eccleston claimed he would otherwise have stayed for two or three more years. Reviewers generally praised the story, though some thought it a little rushed.
Rose sent the Bad Wolf messages out into time to attract her own attention and get her to come to the Doctor’s rescue. The TARDIS probably wanted to do so, and she gave it an excuse. On the Dalek home world, the Doctor’s nickname is The Oncoming Storm. Rose’s resurrection of Jack with the power of the Time Vortex, we later learn, made him basically immortal. It is implied that he becomes the Face of Boe in the end. Jack kisses the Doctor on the mouth—the first same-sex kiss in Doctor Who. The title Parting of the Ways comes originally from Goethe.
Jack was left behind because the writers wanted Rose to be astonished at the Doctor’s regeneration, and it would have been no big deal to Jack. He turns up in the Torchwood series the next year. Torchwood is an anagram of Doctor Who. The fact is: by the second Christopher Eccleston episode, everyone knew that he would appear for only one season and be replaced by David Tennant. As a result, every story of the season was created as a part of the development of the character and written that way. It ended with a hell of a climax.