This is the first time we see Amy Pond. Before Amy becomes the new Doctor's assistant, she is a young girl who is home alone. The young Amy Pond is played by Karen Gillan's cousin Caitlin Blackwood. The Tardis has crashed in the garden and Amy goes out to investigate. The Doctor who has just regenerated into Matt Smith comes out and meets the young Amy. Amy takes The Doctor into her house where he begins to eat anything he can lay his hands on including Fish Fingers dipped in Custard. The Doctor notices a crack in the wall and looks closely at the crack and manages to widen it. A massive eye appears on the crack saying its looking for Prisoner Zero. He promises Amy that he'll come back for her in five minutes and disappears with the Tardis. Amy goes inside and comes back out with a suitcase.
The Doctor returns to the house and enters it, The Doctor gets hit and when he wakes up, there is an adult policewoman there with the Doctor handcuffed to a radiator. The Doctor points to a door and Amy notices the door for the first time and goes in to investigate despite the Doctor saying not to. Inside the room is a large worm creature and Amy runs out. The Doctor frees himself and escapes with Amy. Outside the creature morphs into a man with a door. The man makes dog sounds.
At the local hospital, the comatosed patients are calling for the Doctor and when Rory Williams collects the doctor, nothing happens and then they all start calling the Doctor.
Amy and the Doctor meet up with Rory who's taking pictures. The alien with the dog disappears down a pipe and escapes. The Doctor sends Amy and Rory to the hospital whilst he deals with matters. He later calls the others to tell him he's on his way using a fire engine. The Doctor rescues the humans and confronts the Prisoner One who has turned into a woman with two children. Amy collapses and Prisoner Zero turns into the Doctor. Doctor uses a comatosed Amy to turn the alien into its normal form so the prisoner can be captured by the prison guards.
The Doctor leaves whilst Amy and Rory catch up. The Doctor leaves in the Tardis and returns later to discover its two years on. Amy is in her nightdress and decides to travel with the Doctor.