"When Earth or Sol 3 was formed years ago, one man watched. He was the protector, the saviour, the Doctor. Many people knew him, but some were old, young or alien. Anyone could become the Doctor's friend, his companian. Why? Because the Doctor had a gift to see he talent of everyone, whereever they camefrom, whenever they came from. For that was not his only gift; he could also give his friends experiences they would never forget. He could travel throughout spaxe and time. But the odd thing is, the Doctor is twelve people. All heroes, all magic, all incredible. Twelve faces, bringing hope and danger throughout history. The Doctor, protector, saviour. It only made sense he would come to Earth once more, just to say goodbye." - The Narrator
The episode begins with a monologue spoken by an unknown person about The Doctor begining with the formation of the Earth, and history, including a waiter erving the King a turkey, the inventor of the gun and his ancestor, fighting in WWI. Rose Tyler then poses for a photograph, and hears the TARDIS noise. The picture melts into a picture of Donna Noble and then Amy and Rory.
The Doctor arrives with Ed on Earth in the year Seven Billion. The Doctor goes to investigate, and the two find a Bracewell dalek that survived until now. The two flee, and the Doctor attempts to use his sonic screwdriver on the dalek, a plan which fails when the screwdriver is attracted to a magnet. The Doctor pulls up the screwdriver, but it is now broken. Inside the TARDIS, Ed and the Doctor fly away. Searching for the dalek, the Doctor finds it heading toward a planet called New Skaro. They stow away on the dalek's ship. It detects them, easily however, and the Doctor leaves Ed with the broken screwdriver, piloting the TARDIS to the invention of the gun. He steals ("borrowed!") it and shoots the dalek. Though making no dent in the dalekanium, it does dstract the monster, the Doctor and Ed managing to escape, and return the gun. The dalek arrives on New Skaro. At New Skaro, the dalek proclaims that it killed the Doctor, who then arrives in the TARDIS. The Master Dalek states that the Doctor and by extension all time lords are forgiven for crimes against Skaro. The dalek is then exterminated. The Doctor and Ed are welcomed by the daleks. The TARDIS is taken to be upgraded, as an act of remorse for the Time War. The daleks treat the travellers, but the Doctor does not trus them, as they seem over nice, though the Master Dalek insists this is an attempt to get forgivness.