Amy's all concerned with her, or as far as she knows the Doctor's, engagement ring. It's quite a rock. She can't take her eyes off it, and sitting underneath the TARDIS's main console in a funny little porch-swing situation, she nearly tries it on. Of course the Doctor appears, hanging upside down and being adorable, and yelling in his particularly unhelpful elliptical way about... Something. Something great: Planet One, a field trip to the oldest planet in the universe.
"There's a cliff of pure diamond and according to legend, on the cliff there's writing. Letters fifty feet high, a message from the dawn of time, and no one knows what it says because no one's ever translated it. 'Til today!"
(Um, I can do that for you right now, babe: It is going to say HELLO SWEETIE. That is the only possible thing it can say. Well, BAD WOLF would be funny. WE APOLOGIZE FOR THE INCONVENIENCE. I WASN'T EXPECTING THIS.)
Onward, to "the very first words in recorded history" (a phrase just deathly annoying in its multivalent stupidity, if you think about it), and there they are -- among giant Alice-ish toadstools and on a cliffside not remotely reminiscent of diamond -- HELLO SWEETIE, with the Doctor's old Gallifrey nickname -- just in case it wasn't clear who was being addressed -- and a few random glyphs meant to be coordinates for the next scene.
Except okay, there was no reason for the Doctor to take Amy to Planet One today. I mean, wank it any way that feels good to you, that's my motto, but he honestly just said, for no reason, "I don't know why I didn't think of this before," and then took her to the place so the next stuff could happen. Any other storyline that didn't entirely involve universe-wide changes to the continuum and temporal backdrafts like Vincent painting whatever he painted, I don't suppose it would bother me. This is one of those rare stories where "today" actually counts as "today," because the Cracks are closing in and, as we'll see, the universe is literally getting smaller. Whatever, he's a wizard, and it makes them both tremendously happy, and Amy deserves something at least for taking the trouble to show up this week.
So the coordinates take them to Earth: "Britain. 1:02 AM. No, PM. No, AD..." They stare at a Roman Legion and have a slightly awkward conversation about the various Romans invasions of Britain, which convo is so awkward, in fact, that you're distracted from the main point: Invasion Of The Hot Italians was Amy's favorite thing in school. (Is there something British I'm not getting here, which she uses "topic" the way we might once have used "theme" and would now probably just call an "essay"?)