This Saturday in Manchester, the career of either Amir Khan (19-1) or Marco Antonio Barrera (65-6) will unravel before our very eyes.
What injects this unravelling with such great tension is that for the former, it would end a long and formidable career as a champion across multiple divisions, but for the latter, it delivers a lifetime sentence of what-ifs and what-could-have-beens.
Although only 22, Khan must be acutely aware that losing to Barrera on Saturday will terminate his competitive capital at world level. A hero in Britain, that capital was already heavily devalued with an intelligent left-hook by Colombian fighter Breidis Prescott in September of last year.
The former Olympic silver medallist crumbled on the 54-second mark, and with him fell Britain's vision of an implacable boxing wunderkind.
Since then he has convinced his country fellows, and many more besides, that what they witnessed that night was a hiccup and no more.
He easily eliminated Irishman Oisín Fagan in time for Christmas (though presumably the season went uncelebrated in Khan's camp) and from the spectator's perspective looked good doing so (but like Christmas, there was some fodder for the cynics: Fagan's left fibula was broken during the first knock-down).
Following that victory, an eruption of surprise met the announcement that Khan would be meeting Mexican legend Barrera in March.
It seemed to suggest that the new Khan, under the tutorship of trainer Freddie Roach, was once again willing to take on the world. Could the Bolton boy transform himself into a man before our very eyes?
His promoter Frank Warren would appear to believe so, if we are to go by the title of this spectacle: 'Coming of Age'. But boxers are not characters out of Collodi's Pinocchio. Habits and traits are formed early (Khan first donned gloves at age eight) and flaws are not easily ironed out of a fighter's technique.
There are also the inherent "natural" weaknesses that afflict even the greatest pugilists. Khan's combustible chin needs no introduction here.
I must admit to also feeling some surprise when I found Khan's name nestling next to that of Barrera's for a lightweight bout. Surely he should be nursed toward re-ascension via less challenging opponents?
But from Frank Warren's perspective this bout is a stroke of brilliance. The last thing he needs is another top-name former-Olympian getting knocked out by an unknown (Audley Harrison's recent pounding at the hands of Martin Rogan springs to mind).
At least if Barrera makes mince meat of Khan, he exits with a bang against a champ; but if he wins, he's fast-tracked back to the top with a notable name on his record.
The gamble is also a good one for the spectator. It is, after all, the unknowns that make memorable prizefights: Can one fighter's speed overcome another's power?
How long can defensive trickery hold out when faced with relentless assaults? Will youth prevail over the experience and acumen of the hardened battler?
The 13 extra years Barrera carries into the ring this Saturday are central to that crux. They may allow him to weather an eager Khan, such as Juan Manuel Marquez recently demonstrated against the younger Juan Diaz.
Or they may indeed wear him down, as they did Oscar de la Hoya when he was trounced by a snappy Manny Pacquiao in December.
"If I know Barrera he'll be studying the Prescott tape, and he's going to be looking for the left hook,” Freddie Roach recently told Sky Sports News.
Well, yes. Every one of Khan's future opponents will study that tape. But, to be frank, there really isn't much tape to study. And so I think one of the fights Barrera will scrutinize is Khan's 2008 battle with Michael Gomez.
Gomez, an Irishman who took the Hispanic-sounding moniker in honour of the Mexican 'brawler' style, illustrated how poorly Khan might cope with a determined older opponent.
Although the referee called a halt to the match in Round 5, Gomez upset Khan on a number of occasions, capitalising on his stiff footwork and irresolute defence.
Barrera possesses a more adaptable style and fitter (certainly less beer-laden) physique than Gomez, as well as having fought at a much higher level.
He genuinely seems intent on eliminating his younger opponent from the lightweight rankings and is being driven by the desire to become the first Mexican to win a title in four different weight divisions.
“By the time I was Khan's age I had made six defences of my world title and defeated some great fighters,” he reminded Britain's The Mirror. “I heard all the same talk when I beat ['Prince' Naseem] Hamed, and taking care of Khan will be even easier.”
Such trite talk is the trade of boxers, especially at this level, and Khan's comments prove no different:
"My hand speed, power and don't forget my youth will be a big thing in this fight. It's all about taking him out of his comfort zone and just working and working him," he has said.
For Roach, this means Khan must remain calm and collected. Taking the fight on the back foot, protecting his chin and pocketing fast shots when the chances arise will be the name of the game.
“I told him just to take his time and break this guy down. I told him 'Don't knock him out until he's ready to go'," Roach explains.
The trainer also imparted this useful nugget to his protégé:
"I told him, 'This is your whole life, this one fight'. I said 'If you win this fight, you go on to greatness, if you lose this fight it's over'.”
Jesus of Nazareth could not have delivered it with greater clarity.
For Khan, a victory may well serve as a linchpin in a great career; for Barrera, the opportunity to carve his name ever deeper into the history of boxing.
But on Saturday, it is the loss that will really count. For one, it will mean the furtherance of a dream; for the other, that dream's unravelling.