He's been running alone for so long that it's awkward, at first, having someone to hold his hand - and then two someones, with Jack growing into himself every day and Rose smiling, always smiling, like the Doctor has never done anything wrong. They spill out of the TARDIS, joking and laughing, and sometimes the Doctor thinks he doesn't deserve to be this happy, to have all these new stories and people to travel with - he knows he doesn't deserve it, maybe that's more accurate, but he can't tell them to go away; it would break his hearts and theirs too.

He spins the dials, flies his ship, and flirts with Jack and grins so brightly that he thinks his skin might just split, and he does one thing that he hasn't done in a long time: he thinks about keeping them with him forever, as long as they'd stay, with no worrying about regeneration or Time Lords or war or age; he knows this is a fever dream, an impossibility, but still -- but still -- the Doctor dreams.