In the late 1970s, four gifted boxers rise up to dominate the sport and define an era: Sugar Ray Leonard, Marvin Hagler, Tommy Hearns and Roberto Duran. Leonard is the all-American feted as 'the new Ali.' In contrast, Hagler takes the hard road to the top, and he doesn't owe the world any favors. Tommy Hearns steps into the ring in Detroit, knocking out most of his opponents in devastating fashion. But it's Roberto Duran whom Leonard sets his sights on to prove he's more than just a TV personality. Series premiere. Written by SHOWTIME

Gentle giant Tommy Hearns represents Detroit's hopes and dreams and after a devastating title fight, he's crowned champion. In the aftermath of the presidential election, Ray Leonard again challenges Roberto Duran, leading to one of the most notorious endings in fight history. Meanwhile Marvin Hagler is given a second chance at glory, but a riot breaks out in England after his victory over the local champion. The stars now align for one of the greatest fights of all time: Leonard vs Hearns. Few could have predicted how the day would go down. Written by SHOWTIME

Following his defeat of Hearns, Leonard ascends the throne vacated by Muhammad Ali. But the aftermath brings the revelation of an eye injury - and Leonard announces his retirement, robbing Hagler of the fight he'd been spoiling for. Duran hits rock bottom, a pariah not only abroad but in his home country. Nevertheless, he stages a miraculous comeback. With Leonard and Duran out of the way, the stage is set for one of the greatest fights of all time: Hagler vs Hearns. Written by SHOWTIME

The era of the Four Kings comes to an end. Hagler defeats Hearns and claims his place at the top of the world. Ray Leonard comes out of retirement to challenge the new champ. Following their fight, Hagler is disgusted with the verdict and quits. Tommy Hearns finally gets his rematch with Leonard. Hearns devastates Leonard, leading to another controversial decision by the judges. Leonard and Duran come together for a final fight, a pale imitation of their former glories. It's the end of an era, but the Kings' legacy is assured. Series finale. Written by SHOWTIME