If Peter tells him one more time to not look for Kate, Neal thinks he might explode.
"The bottle meant goodbye."
But words aren't enough: he has to literally bury the damn bottle before Peter is willing to believe him.
It's hard to pretend that Kate's dead when he knows she isn't, but he's a con man, and sincerity of lies is his life.
"I am sorry," Peter tells him.
"Yeah," Neal says, and while his grief is feigned, his distraction isn't. He hesitates, then gives his consultant badge back. "Peter, I can't... I can't do this."
He buries the wine bottle, because he doesn't need it any more, not when he has the real thing coming.
Neal isn't sure whether or not he regrets his decision. On the one hand, if he'd gotten on the plane with Kate, he'd have had time with her. Not much time, because there was only an hour between the plane taking off and the plane blowing up over the Atlantic, but any time is good.
On the other hand, he'd be dead.
(On the other other hand, he feels pretty damn dead, knowing that he's lost her for good.)
There is no body to bury, so instead he takes their wine bottle, promise of a better future -- ha! -- and buries it along with his hopes of their potential.
"Bye, Kate," he whispers, and receives no response, cryptic or clear.
Fragments of the plane remain, charred at the edges. The rest is ash, and they can't separate what was once living from what wasn't, so Neal has no way to bury Kate.
Except, of course, with their wine bottle.
He buries it next to her father's grave, and watches as the earth covers first the label (shouldn't paper beat rock?) and then the bottle and then it's just soil on soil. His vision is, perhaps, swimming with tears, but it is as steady as he can make it, watching the bottle disappear. One last magic trick.
He knows that it will be seared into his memory forever, but he still comes back occasionally, digs up the grave (federal offense? he doesn't care), and holds the dirt-stained bottle in his hands. Sometimes he takes out the ink sketch of Kate that he'd stored inside, so he doesn't ever forget her face.
And then he buries it all over again.
Peter pays for the cremation, and then funnels the ashes into a wine bottle -- not a Bordeaux, but the closest he can find -- and stoppers it with a gilded cherub. (That, the missing piece of the music box, comes to Peter in an anonymous, untraceable package, along with a note in handwriting he doesn't recognize; he contemplates using it to find out the secrets of the box, but the thing has already caused too much damage and trouble.)
(Because of it, Neal is gone.)
... it isn't that simple, of course, isn't ever that simple. but Peter doesn't really care.
"For what it's worth, I'm sorry," he says to the wine bottle in his hands, heavy with all it contains. He can still picture the wistful fondness in Neal's face when he'd explained what the empty wine bottle meant to him, to Kate.
Now it means something entirely different.
They tell him that if Neal had been ten feet farther away from the plane, or if the bomb hadn't been as powerful as it was, he might have survived.
(Or if, Peter sometimes thinks, he'd gotten there sooner...)
But a world of ifs can't change the reality of what is.