Tennis star and women’s rights activist Billie Jean King won a total of 12 Grand Slam titles, but the biggest match of her career took place in 1973 against former men’s champion Bobby Riggs, a self-proclaimed male chauvinist pig who declared that, even at the age of 55, he could beat any woman in the world.

The first time Chris Evert and Martina Navratilova stepped onto a tennis court together, the world scarcely noticed. Only a few hundred spectators saw the pert 18-year-old beat the scrappy 16-year-old Czech in 1973. “I remember that she was fat,” Evert recalled. “She was very emotional on the court, whining if she didn't feel she was playing well. But I remember thinking, if she loses weight, we’re all in trouble.” Said Navratilova, “My goal was for her to remember my name.” Eighty matches later – amid the extraordinary growth of women’s tennis – Evert not only remembered, but became a tried and true friend and confidante, remarkable considering the two appeared to be polar opposites in upbringing, life styles and personal relationships. Through a series of personal conversations, this documentary will tell the story of one of the greatest one-on-one sports rivalries and capture these two extraordinary athletes’ views on tennis and an ever-changing world.