In the span of several months, he takes Amy to some of the most gorgeous, breathtaking spots in the universe - silver forests where the wind sings, crystal waterfalls underneath green skies, deserts covered in sparkling sand lit by twin moons. Of course, there is Rio, and for once they are dressed for the occasion. The Doctor watches her happily party through the streets of downtown Rio with a group of cute Brazilians and thinks he must be getting better at faking it because Amy never seems to suspect that he's not enjoying himself as much as she is, not when he's the only one that knows their party is missing one person. And it's all his fault.
Still, it's not his Time Lord guilt that should be the center of his attention. Cosmic angst is so last regeneration, chucked out with the Chucks and the boring ties. So the Doctor makes his primary mission that of Amy's happiness (with the occasional rescue of a random civilization on the side) because that's what he wants. That's what he wants and that's what Rory would want, as presumptuous as it is to assume Rory's wishes. The dead boy. The boy who was wiped from time and space. The boy who only exists inside the head of a 900-year-old man who already has enough ghosts of companions past crammed inside his cranial case.
The TARDIS is en route to a holiday planet where the clouds reflect light like crystals and soft rainbows fall onto the earth's surface like rays of sunlight and the people talk as though each word is a melody; another beautiful place to make Amy forget that she's forgotten something, when the Doctor notices her leaning against the upper railings of the console room, arms folded neatly against her chest. Her gaze rests somewhere in the distance, in a place beyond the TARDIS' walls, where neither of them can reach. She looks ready to cry and she doesn't know why she does except for the overwhelming sense of loss coming undone in her chest with no rhyme or reason to it but she knows if she asks the Doctor, the mad man with a box who has lost so much already and would know all the right words to say, then she might actually learn the truth. She might actually find out why she's been breaking into tears for no reason at all at odd moments since the Silurians and the answer to it all might kill her in the end.
So when the Doctor catches her eye, she smiles as if nothing is wrong and hides behind another comment about the Doctor's erratic piloting skills that makes him indignant and makes her laugh. The TARDIS shudders as it passes through the vortex and amid the frenzy of grabbing onto the nearest thing and holding on for dear life, the non-moment passes and Amy once again forgets that just seconds ago she had been on the verge of breaking down over a memory lost.
Over the sound of the engines groaning against the parking brakes, the Doctor shouts something about how Amy is going to love this planet and starts describing the rainbows and the people. Amy shouts back, asking if they ever have any fun on this planet then lets out a squeak as the TARDIS comes to a halt, the familiar sounds of materialization fading out in the console room.
In the absence of the usual sounds from the old girl, the Time Lord's oddly quiet voice reaches Amy's ears like a gunshot. "I could tell you," the Doctor says with that mischievous look of his, "but what fun would that be?"
Without another word, the Doctor touches a lever on the console then runs to the TARDIS doors with all the grace of an awkward adolescent giraffe. Being the typical Mister Cool that he is, he manages to sneak a glance over his shoulder as he 'walks' and sees Amy following on his heels, the back of her skirt drifting behind her long legs lazily. She's smiling and laughing at the Time Lord's typical gait and this for the moment being is good enough.
For one moment, the smell of freshly cut grass and the sound of Amy's laughter mixed with the song-speech of the people around them makes the small velvet-lined box in the Doctor's pocket feel as heavy as air.