Lil’ Wayne music blasts through the stereo as a Celtics fan, we’ll call him Dennis, drives his car to McDonald’s.  Dennis nods his head softly to the beat as he laments the Celtics’ plight.

Down 3-1. Needing to win three straight games, including two on the road. Rajon Rondo has one arm. Kevin Garnett can’t bring it every night. Ray Allen productivity fades in and out. Glen Davis’s mind has fallen victim to demons. Jeff Green hasn’t done enough, Paul Pierce can’t do it by himself, and Lebron James and Dwyane Wade have never played better together. Things sound bleak.

One of Dennis’s favorite songs is playing. Get Over, it’s called. But he isn’t concentrating on the song, because he can’t stop thinking about the Celtics. Maybe their time has come. Maybe it was always meant to end like this, at the hands of the next trio of stars, with blame spread like blood across age, an uncharacteristic lack of execution and, yes, Danny Ainge. After all, this is how NBA eras end, how the baton passes from one team to the next, how one team realizes its mortality while another struts toward immortalizing itself.

Dennis worries about so much, but somehow, despite so much evidence saying the Heat are now the better team, he remains oddly confident in the Celtics. He’s been through enough with this team that he expects a heroic response to going down 3-1. Maybe that response is somewhat irrational, allowing events from years past to influence how he feels about the present. But he has faith in this team. He remembers the Red Sox’s rallying cry from 2004: Why not us? But still, he knows in the back of his mind, tonight could be the end.

It’s just a sport, Dennis realizes, but “just a sport” means a lot more than some people think. You watch a team for 82 games every season, plus the playoffs, and you begin to identify with the players in ways normally reserved for tight friends. You learn that Kevin Garnett will scream until his lungs hurt, at his teammates, at his opponents, at nobody in particular. That Paul Pierce loves his stepback jumper, and that he leans ever-so-slightly to help direct his three-pointers into the hoop. That Ray Allen rarely shows much emotion, but when he does it’s usually either a small fist pump or a jumping celebration where Ray leaps into the air, turns his body, and bumps backs with one of his teammates. That Rajon Rondo loves fake around-the-back passes, Connect Four, and right-handed scoop shots from the left side of the hoop.

This team has given Dennis so much pleasure since the summer of 2007. The title run of ’08. The first-round series against Chicago in ’09. The Glen Davis game-winner the same year. The unexpected run to the Finals in ’10. The never-quit, never-lose-confidence, never-stop-playing-defense attitude the whole way through. Dennis can forgive the Big Three era Celtics for their laissez-faire effort during the past two regular seasons; partly because they returned Celtic Pride after two decades of mostly bleh, partly because they played so damn hard whenever games truly meant something.

As Dennis thinks about the entire era, the Lil’ Wayne song continues to play. The lyrics, which he had hardly been listening to, suddenly strike him:

Lord, will I be next for the taking? Take me

I know I’m living like I know when I’m coming

But I’m just living ’cause I know that it’s coming

And the end is coming, but I ain’t running

I ain’t hiding or ducking

I’m in the middle of a war, I’m alive and love it

Dennis knows Lil’ Wayne isn’t rhyming about the Big Three (he’s a Lakers fan, isn’t he?), but the words seem so perfect. The end is coming for the Celtics. Maybe not the end of the Big Three era, but at least the end of their run as conference front-runners. Hell, the end has always been coming, ever since Danny Ainge assembled a team built around three superstars at or nearing the end of their primes. There was always the belief that this team’s greatness was fleeting, the feeling that this could end at any time with one more injury, one more deteriorating body. But now more than ever, or at least more than at any point since last summer, when Game 7 was followed by the uncertainty of a few contract situations, the end hovers like the clingiest girlfriend over every step the Celtics make.

The end could come tonight, or Friday, or next week, or next year. The point is, it’s inevitable. It always has been. It always will be, for every NBA team. But especially for the Celtics, joined not in youth but in the latter years of glory, the end has always felt closer than it does for most great teams. That’s part of what has made this Celtics team so great, the urgency they had not just to win, but to win immediately.

Doc Rivers remembered when the Big Three were assembled and everyone figured they would take at least a year or two to mesh.

“We don’t have that,” he thought at the time. “‘You just don’t know with health.”

Now, down 3-1 against the surging Miami Heat, the end seems almost tangible. Yet the Celtics have never run from it. They live every day like they know when it’s coming, not because they do, but because they know that at some point, it will finally catch up to them. They’ve never hidden or ducked from it. They’re in the middle of a war, even now, even down 3-1. They’re alive and love it. As long as they’re alive, they love it.

Dennis, still oddly confident, still worried as hell, wants to soak in every last moment, for better or worse. This is one war he wishes could go on forever.