"The Impossible Astronaut"
So, what a fantastic start to Season Six! The Doctor is killed by a spaceman from the lake after being blasted by his gun and prevented from regenerating. Amy, Rory, and River cry about his demise, but decide to meet up with where the envelope told them at a diner. Unexpectedly, they find The Doctor already there. The Doctor doesn't realise that his other self has died, so the others don't tell him. They go to the White House in 1969 and discover President Nixon is there and they get surrounded by agents. The Doctor tells them they can help them work out who the voice is on the recorder that's been haunting him. Amy, Rory, and River think it's the Spaceman and whilst Amy goes to the Bathroom she discovers an alien called The Silence, in which only people can remember them when they see them. Amy tries to counter this by taking a photo of it on her phone. After finding the location of the girl, they go to the building and discover a control room. The Silence are slowly creeping in on them and the episode ends with the Spaceman revealling to be the little girl and Amy reaching out for the gun and firing at the Spaceman.