Sweet Thunder chronicles Sugar Ray Robinson's exploits with an emphasis on an intriguing aspect of the fighter's early career. Despite being the class of his field in the welterweight and later middleweight class, Robinson spent too long watching inferior fighters get title matches, boxers that he'd whipped soundly in non-title fights. The reason: boxing was controlled by organized crime, and Robinson declined to get in bed with them, and refused to throw a fight. Robinson helped expose that seedy underbelly of the business.