A Swiss businessman with a waxed moustache starts his daily commute to the office. He takes the train and from the carriage window sees a motley group of youngsters kicking what could be described as a primitive ball on a strip of wasteland.
Intrigued, the man gets off at the next stop, tracks back and asks if he can take part. Accepted by his new team-mates, he jogs out on to the pitch and doesn't take long to make his influence felt.
He unleashes a shot of such force that the ball, perhaps nothing more than a tightly bound collection of rags, falls apart. Embarrassed, the man apologises profusely and, to make up for his transgression, promises to order another two from back home in Switzerland.
That man was Hans Kamper and he is acknowledged as the founder of FC Barcelona. On October 22, 1899 he placed an advertisement in the sports paper Los Deportes to let the locals know that he was "keen on organising some football games and encourages anyone who feels enthusiastic enough about the sport to make themselves present."
Kamper soon became an adopted son of the city, assuming the Catalan name Joan Gamper, and since 1966 Barcelona have organised a trophy in his honour.
Initially a four-team tournament, the Gamper is now a one-off exhibition match. It is a celebration of Barcelonismo, and tonight Pep Guardiola's side play host to Napoli, a club they have met just once before in a friendly at the San Paolo in 1978.
That night Johan Cruyff's saying that "Italians can never beat you, but you can lose to them" almost came true. The game ended 1-1 with a header from Moreno Ferrario cancelling out a goal scored by Esteban.
"Barcelona have always been at the vanguard," recalled Gianni Di Marzio, Napoli's coach in the late '70s. "For example, at the time Rinus Michels sat on the bench, the prophet of total football.
He played zonal marking with three strikers. Guardiola's team seems like a photocopy of the one we faced."
But what links Napoli and Barcelona is not a deep rivalry or a rich history of past encounters. It is, quite simply, Diego Armando Maradona. The story of his discovery is remarkable for the insight it gives into scouting at the time.
In early 1977, Nicolau Casaus Ã¢ÂÂ an Argentine ÃÂ©migrÃÂ© who, a year later, would become Barcelona vice-president under the Josep LluÃÂs NÃÂºÃÂ±ez regime Ã¢ÂÂ received a phone call from an old friend by the name of BeltrÃÂ¡n.
A cake shop owner from Mar del Plata, 250 miles south of Buenos Aires, BeltrÃÂ¡n had recently watched the 16-year-old Maradona inspire Argentinos Juniors to victory Ã¢ÂÂ and recommended that the kid be signed immediately by Barcelona. But BarÃÂ§a would instead wait five years Ã¢ÂÂ and spend a world-record ÃÂ£5 million Ã¢ÂÂ to capture him.
As for Napoli, they had first heard of El Diego when an engineer who had emigrated from Italy to Argentina collared Di Marzio in the lobby of the Don Carlos hotel in Buenos Aires during the 1978 World Cup. Di Marzio ignored him a couple of times Ã¢ÂÂ then relented and went to watch Maradona play in a club friendly.
"We arrived at the ground, the pitch was all beaten up, the two teams were ready, but Diego wasn't there. We had to go to his house in Villa Fiorito. It took us a while to make him come with us. He was angry with [then national team coach] CÃÂ©sar Luis Menotti for not calling him up. In quarter of an hour he scored three goals."
Di Marzio claims he could have signed Maradona for $220,000 there and then, only for Napoli president Corrado Ferlaino to balk at paying such a figure for a youngster. They missed their opportunity and El Pibe de Oro arrived at Barcelona in 1982 for just over $5 million.
The Catalonia years are retold in the chapter of MaradonaÃ¢ÂÂs autobiography entitled: The Frustration. He was eclipsed by Bernd Schuster, contracted hepatitis, played a part in ousting his first manager at the club Udo Lattek because he insisted on training early and with 8kg medicine balls.
While the appointment of Menotti placated Maradona to an extent, he still acted up, even throwing a Teresa Herrera piece of silverware to the floor in Barcelona's trophy room when NÃÂºÃÂ±ez confiscated his passport and stopped him from playing in Paul Breitner's testimonial before the final of the Copa del Rey.
Then came that tackle from the Athletic Bilbao hatchet man Andoni Goikoetxea. "My time at Barcelona was always ill-fated," Maradona wrote. "Because of the hepatitis, because of the fracture, because of the city as well, because I'm more... more Madrid."
He joined Napoli on June 29, 1984 as Ferlaino wrote a cheque for 15.8 billion lire (ÃÂ£6.6 million), and after performing a few kick-ups in front of 40,000 fans stood in the San Paolo's Curva B, he said: "I want to become the idol of the poor kids of this city because they are like I was when I lived in Buenos Aires."
Maradona was everything and more. He was the people's champion, granting a city and a region the recognition and the status that it had lacked by leading Napoli to their first and only Scudetti in 1987 and 1990.
Famously during that era a piece of graffiti appeared on the walls of the city graveyard: "Guagliu!" it read. "E che ve sit pers! You don't know what you're missing!"
The 8,000 Napoli fans who have travelled to Barcelona will perhaps bear that message in mind when they watch their team walk out on to the pitch at the Camp Nou. For this is mÃÂ©s que un friendly for a club that is officially back in the big time, their qualification for this season's Champions League coming seven years after bankruptcy and a place in Italy's third division.
"History says that only the big clubs can come and play in this stadium," Napoli coach Walter Mazzarri explained. "What we have done in recent seasons has made us important too, to the point of deserving an invite from the best club in the world."
Tonight Napoli are looking to become only the second Italian team to win the Gamper Trophy after Fabio Capello's Juventus lifted it in 2005 following a penalty shoot-out.
"They have many champions," said Napoli's new signing GÃÂ¶khan Inler, "but anything is possible. In football you can never take anything for granted, you can never say never. With Switzerland we also beat Spain."
Played under the shadow of Maradona, and in light of his heir Lionel Messi, itÃ¢ÂÂs a friendly not to be missed.