It is the first time Amy Pond goes travelling with The Doctor and she's still in her nightie. After enabling Amy to float in space outside the Tardis with The Doctor holding onto Amy's ankle. They land on the Starship UK which has tower blocks named after counties of the UK such as Kent and Surrey.
Children are disappearing after selecting an option on a machine, where the two options are Forget or Protest. When Amy gets the opportunity to press either of the buttons, she presses Forget. When the Doctor meets up with Amy, he manages to watch the video that Amy had just made before she pressed the button. The Doctor presses Protest and the floor disappears and the two go through a cute to an underground sludge. A tsunami of dirty water comes at them but are unable to avoid. They manage to escape.
They meet a woman who says she is Elizabeth X, the tenth queen of that name for the United Kingdom. Elizabeth tells the Doctor the situation and why she wears a mask to hide her identity. She takes them to the Tower where everything is revealed. The starship is on top of a giant space whale which is controlled by lasers hitting the brain to direct it. Every ten years, the queen finds out the truth and has her memory wiped.
Whilst the Doctor decides what next to do, Amy slams the Abdicate button on the control freeing the space whale. The whale doesn't leave but remains with the starship and moves faster through space.
The Doctor and Amy make amends and return to the Tardis. They receive a phone call from a Prime Minister who turns out to be Sir Winston Churchill who has an unlikely friend in the form of a Dalek.