The Doctor is forced to find somewhere to stay until he can bring the TARDIS back. The Doctor finds the perfect place at the home of Craig who had placed an advert in the paper for a lodger. Craig accepts the Doctor who then moves in with Craig. Throughout the episode, Amy is trapped on board the TARDIS with a communications link with the Doctor to help her fly the Police Box
Over the course of the episode, passer-bys are enticed into the building and up into the flat above the flat that the Doctor is staying at. The passer-bys are enticed by someone calling out to them not by name but requiring assistance. It happens three times and each time, the person is not seen again.
The Doctor ingrains himself more and more in Craigs life. Craig invites the Doctor to a football match which the Doctor accepts. The Doctor becomes the man of the match scoring so many goals. When Craig has to take a penalty, the Doctor can't let up and steals the opportunity and scores.
Throughout the episode, the ceiling of the lounge in Craig's flat gets a dark patch which grows over time. The Doctor tells Craig he must not touch it. Craig's curiosity gets the better of him and he touches the dark spot. Craig falls ill and The Doctor tries to nurse him back to health. When Craig isn't able to go to work, the Doctor takes Craigs place and is an instant hit with the colleagues.
Craig orders The Doctor to leave but when its discovered that Sophie, who is Craigs friend, who had appeared throughout the episode is missing after entering the flat, the Doctor and Craig decide to visit and break into the flat above. Amy has revealed that the building plans should show that the building is only one floor, the second floor should not exist. Inside the flat above, the Doctor discovers that its a cloaking device for an alien craft that wants to get back home.
The only way it can go back is if it had a pilot which it had been enticing people in to find out if they were right. Only people who want to leave their surroundings are targets for the alien. As Craig didn't want to leave, Craig was safe from the alien craft. Sophie is being pulled to the machine when the Doctor intervenes and is instead pulled to the machine. Craig saves the day by touching the machine. Craig never wants to leave so pressing the machine disables the machine. The machine leaves the surroundings returning the building as it was. Craig and Sophie become more than just friends now. The TARDIS finally lands and the Doctor leaves.