The old warrior and the son of the man he killed sit together on a bench in Central Park and cry in one of those moments that is cold and raw, yet warm and healing at the same time.

The old warrior is Emile Griffith, a six-time world champion whose 20-year career as a fighter and a dozen more as a trainer has been crystallized to one moment – one horrific round at Madison Square Garden in 1962.

The other man is Benny Paret Jr., the only son of a brash, prolific fighter who taunted Mr. Griffith before their third fight and paid for it with his life.

It is a bout that should not have happened. Paret was a broken-down fighter at the time, a man who shouldn’t have been allowed into the ring.

But greed has long been a virtue among the men who control boxing and Paret’s manager was determined to squeeze out one more big payday.

Now, 43 years later, the night that nearly led to the abolition of boxing is the subject of a wonderful documentary from a New York public relations guru and filmmaker, Dan Klores.

The film, “Ring of Fire,” premiered at the Sundance Film Festival Saturday and opens soon in New York. It is not to be missed.

“My intention always was to make this into a love story, not a boxing film,” Mr. Klores says. “It’s about the love Emile Griffith has in his heart for his family and for his sport, and the love Lucy Paret and Benny Jr. have for each other and for the man who was a husband and father. It’s also about forgiveness.”

The film opens with the fight, in grainy black and white with the amateurish graphics of early TV, and cuts in some historical and cultural background before going to the last flurry of fatal punches.

Mr. Griffith and Paret each won one of their previous fights. Both were wars. Paret had been badly beaten in a couple of fights before this showdown and the night before the bout he called his wife and said he was too sick to fight. His manager, Manuel Alfaro, wouldn’t let him cancel.

Tensions were running high. At the weigh-in, Paret called Mr. Griffith a maricon, a derogatory Spanish term for homosexual. Many in the macho boxing world believed Mr. Griffith was gay; he vowed to pummel Paret.

Mr. Griffith controlled the fight early, but Paret caught him with a left at the end of the sixth round, knocking him to the canvas.

Mr. Griffith soon regained control and in the 12th he backed Paret into the corner and threw at least 18 clean, unanswered shots to Paret’s head in about five seconds. Finally, referee Ruby Goldstein, considered one of the best, jumped in, but it was too late.

Paret, his face swollen and beaten bloody, drooped from the ropes in the corner and slid to the ground. He died nine days later, never regaining consciousness.

It was nearly the death of boxing. Pompous politicians called for investigations – which produced nothing – and the sponsors pulled out of the weekly fights, which soon went off the air.

Benny Paret was buried in the Bronx, but his ghost lived on to haunt Emile Griffith – who kept fighting but was never really the same – along with Ruby Goldstein, Lucy Paret, and Benny Jr.

The ghosts haunted Mr. Klores, whose film is an exorcism of sorts.

“Emile was glad to do the film, because I think he wanted the relief of confronting the ghosts,” Mr. Klores says. “It took a long time to get him to warm, though, because these are the two most delicate issues of his personality: the death of Benny Paret and [Mr. Griffith’s] sexuality.” It took Mr. Klores 20 hours of taping to get 15 minutes’ worth of material because of Mr. Griffith’s “memory issues.”

Mrs. Paret, hauntingly attractive then and now, cooperated but would not agree to meet Mr. Griffith. Benny Jr. jumped at the chance.

It took place in October 2003, a chilly fall day full of blowing leaves and gusting memories. They hugged repeatedly and spoke for a long time.

“I didn’t mean to kill your daddy,” Mr. Griffith said at one point.

“We know that,” said Benny Jr., who was 3 when his father was killed and who never saw that fatal fight until Mr. Klores made his film.

As the camera moves back and the credits roll, the old warrior and the son of the man he killed sit close together, whispering, but speaking loudly enough to drive away the ghosts.