The sixth season of the revived Doctor Who begins in the most unlikely of places: under a woman's hoop skirt. Sometime in England's history, the Doctor is locked up in the Tower of London for improper relations with a member of the court, but escapes by means of a "magical sphere." In 2011, Amy and Rory, his companions, learn about this as they search through history books and old movies for little clues left by the Doctor to his whereabouts. As Rory misses him in an old Laurel and Hardy movie, Amy receives a "TARDIS Blue" letter giving coordinates and a time to meet up. She pays no mind to the number "3" printed on it.
Somewhere in the 51st century, Dr. River Song receives a similar letter and, as one of the guards puts it, "she's going to some planet called 'America.'"
Back in 2011, Amy and Rory get off a school bus in the middle of nowhere, Utah. Once Rory complains about their location, the Doctor makes his presence known. He sits on a classic car and greets his old friends. They remark on his Stetson. "I wear a Stetson now. Stetsons are cool," says the Doctor before the hat is shot off his head by River, who then offers her customary greeting: "Hello, Sweetie."
The group makes its way to a diner, where the Doctor and River sync up their diaries and get a feel for where they are on each others' time-lines. They've been to Easter Island and met Jim the Fish. "Still building his dam," the Doctor says. After Amy explains the diaries to Rory, the Doctor admits that it is time for him to stop running. He tells them they are going to "Space: 1969."
Following the credits, the group is having a picnic on the shore of some out-of-the-way lake. The Doctor reveals he's 1,103 years old. The last time Amy and Rory saw him, he was 908. In the distance, Amy sees a shape, but lets it go as a car drives up. An old man gets out of the car, but everyone looks to the lake and the Apollo-era astronaut that appears in it. The Doctor goes up to talk whoever might be in the suit. The Doctor knows precisely who is inside and is unfazed when the faceplate lifts up. He seems to know what is about to happen. The Astronaut shoots the Doctor and then quickly shoots him again in the midst of the regeneration cycle.
The Doctor is dead.
The old man, Canton Everett Delaware III, gives River a tank of gasoline, saying the Doctor knew that they would need it. The group gives him a Viking funeral by means of a nearby boat. Before Delaware leaves, he tells them that they will all see him again, but he will not see them.
Back at the diner, River mentions Delaware had a letter with a "4" printed on it. As her letter is the second, she ponders who might have received the first. She notices the "1" letter on a table and the Doctor emerges, alive, from the back room where the TARDIS has landed. "This is cold, even by your standards," River says. Oblivious to what they've experienced, the Doctor is thrilled to see his friends all together. River slaps him. The Doctor tells them that he is 909 and that he has no memory of Jim the Fish. The group tells the Doctor they must go to 1969 and find Delaware.
In the TARDIS, Amy, Rory and River agree not to tell the Doctor that they watched him die. As always with time travel, becoming aware of future events could be disastrous.
The Doctor announces he's taking all of them home and that he thinks they are being coerced into this mission. When Amy says that is not the case, he makes her swear on something important. She swears on "fish fingers and custard." Once convinced, the Doctor takes them to Saturday, April 8, 1969. "Saturdays are important," the Doctor says, "big temporal tipping points where anything is possible."
They materialize, cloaked, in the Oval Office, where President Nixon is briefing Delaware on a phone call he gets every day to his private line. It is the voice of a young boy or girl -- Nixon's convinced it's a boy -- asking for his help and calling himself "Jefferson Adams Hamilton." The child says he (or she) is scared of "the Spaceman." They spot the Doctor taking notes. Nixon calls for the Secret Service and Delaware tackles the Doctor. River de-cloaks the TARDIS and walks out with Amy and Rory close behind. The Doctor manages to convince Delaware that he can help them with the problem, but in order to do it, he needs street maps of Florida, "12 Jammie Dodgers and a fez."
Amy asks River if it could be the same "spaceman" they saw at the lake. River replies, "Probably," just as Amy sees a creature in the doorway of the Oval Office, recognizing it from the lake. She starts to feel sick and asks for a restroom. Once there, she sees the creature again. It destroys a woman who walked out of one of the stalls and orders Amy to tell the Doctor "what he must know and what he must never know." Amy manages to take a picture of the creature.
As soon as she leaves the restroom, Amy forgets everything that just happened.
Back in the Oval Office, the Doctor never gets his fez, but does look at the maps and figures out what to do just as Nixon gets his call from the child. Oh, also, the child is definitely a girl. The Doctor gets everybody back into the TARDIS and tells Delaware not to follow him. Of course, he does just as Nixon tells the girl he is sending his "top men" to deal with the spaceman.
The TARDIS materializes in an abandoned warehouse near Cape Kennedy Space Center in Florida. As they exit the ship, Rory is left to explain all the vagaries of time/space travel to Delaware. The Doctor shows River that "Jefferson Adams Hamilton" was not a name, but a location; that is, an intersection of streets. She tries to hide the fact that she is impressed with his cleverness. The group explores the place and finds various alien gear and stolen NASA spacesuits. The Doctor assumes that it is a trap, but presses on. Soon, they find a manhole opened up with odd alien cables coming from it. River goes down the hole and sees more of the creatures. When she gets back to the surface, she forgets what she saw and suggests going back down. The Doctor sends Rory with her.
Below, River and Rory find a locked door. As she tries to open it, she tells Rory about the day she dreads -- the day she will meet the Doctor, but he "won't have the faintest idea who I am." When the door unlocks, she adds, "And I think it will kill me." The door opens to a TARDIS-like control room; one that resembles the time ship from last season's episode "The Lodger." She also finds out that the tunnels they discovered are old and go across the planet. Rory sees the creatures coming closer, but keeps forgetting every time he looks back at River. She finally looks up and yells "Rory!" as light flashes at her.
Up top, Amy tries to tell the Doctor something important as Delaware hears the girl calling for help and runs off. They find him doubled over as Amy finally lets out that she's pregnant. In the distance, the astronaut appears. Keeping the idea that she can change The Doctor's future in mind, Amy picks up Delaware's gun and shoots at the suit ... only to see the little girl inside!
The story continues next week in "Day of the Moon."