Summoned to Utah, Amy, Rory, and River Song meet up the Doctor, who offers to take them to space in 1969, in the episode "The Impossible Astronaut." Before they go, they stop for a picnic by Lake Silencio, where they witness an astronaut in full regalia emerge from the water and murder the Doctor.
While mourning the death of the Doctor, the surviving trio meet at the diner and discover another version the Doctor, one from before he had died on the lakeside. Without telling the Doctor about his death, the group travels back to Washington, D.C. in 1969. There, they must work with Richard Nixon and Secret Service Agent Canton Delaware III to thwart an invasion by The Silence — a race of hideous aliens who can only be remembered while being observed.
