The Doctor pulls all manner of historical stunts to get the Ponds’ attention — which makes zero sense, if you even think about it for like one second — and finally invites them to a picnic with River and the old man version of Canton Delaware III (a.k.a. Badger Lampkin, whom we’ll meet later). An Apollo-era spaceman shows up and murders the 1100-year-old Doctor, in a way where there’s no regeneration possible: He’s just dead. The end.
Amy and River, of course, freak right out — although as usual, River seems to know more than she’s telling — and then amidst much whinging and funeral-planning, our usual 900-year-old Doctor shows up, having received the fourth of the invites from his 1100-year-old self. Amy and River freak right out once again, but get everybody on board with keeping his murder a secret from our Doctor until they can somehow set it right. (River doesn’t think it’s possible, Amy’s all “time can be rewritten blah blah” like usual. Also, they both have stomach pains that either have to do with the Silence or, in Amy’s case, the Rory spawn parasites inside her womb.)
The three of them head back to 1969 to help Richard Nixon with a spaceman-related problem, and we finally meet the Silence: They look essentially identical to the Gentlemen from Buffy, and you completely forget they exist except when you’re looking for them. Amy has a run-in with one of them that is super-eerie, and then forgets about them despite having snapped a pic with her phone that will probably be pivotal next week.