Rule Two

They're lying on their backs in the thick green grass of another strange planet they've just saved, shoes kicked off, watching faint wisps of cloud scoot across a faintly purplish sky and he's telling her the almost completely fictitious version of how he shut down the engines of the rocket that someone had overloaded in hopes of blowing half the city to bits. She's laughing at his tale of bravery and he's pretty sure she knows he's making it up as he goes so flips onto his side and looks into her eyes and says very very seriously

"Why do you stay with me, River Song?"

(I lie and I run and I break their hearts and I'm drenched in the blood of civilizations and—)

She knows exactly what questions are layered behind those eight words. She gives him one of her arch know-it-all grins and he expects "Spoilers " but she says "Rule Two."

He hasn't got a Rule Two.

He's run through his mental list of Rules (of course he remembers them all) but in typical fashion he doesn't come up with them in order but only in importance. Apparently he's never come up with a Rule that's important enough to be Number Two.

Then he meets a young, young River Song and even as he's dying he tells her "You might want to write these down" because he can't stand an unsolved mystery and right now Rule Two is the biggest one he's got.

Write them down, River. Write them down so I can give you the words that will make you stay.

They're properly married the next time he thinks of Rule Two. "I know what it is," he tells her, hoping to get her to let slip a clue, but she gives him a different smile. The one she saves for when he's being very sweet or very stupid (or mostly both).

(I am telling you.)

"No you don't," she says softly, and he begins to wonder if he ever will.

River's gone and he's kept the journal.

It's all he has left of her, really, and he keeps it in his bigger-on-the-inside coat pocket next to his left heart.

After awhile he's able to bring himself to open it and the very first thing he looks for is Rule Two.

He finds all the Rules written down in very precise order, in proper order, number by number. And he feels a furnace-hot blow of Pride and Grief that she saw through him that clearly when, neatly penciled below

Rule One: The Doctor lies

he sees the words

Rule Two: But only to himself.