Masters of Sex has been cancelled by Showtime after four seasons, leaving the story of Bill and Virginia Johnson unfinished.

When Masters of Sex began, it felt like one of the best kept secrets on television, a smart, subversive, and clinically sensual comedy about the repression of 1950s and ‘60s white America. And unlike its AMC contemporary, Mad Men, being on premium cable allowed it to indulge in the kinks Don Draper could only ever imply.
Alas, it seems the secret was too well kept since Showtime has apparently cancelled Masters of Sex two weeks after its fourth season concluded. The news was broken via Deadline, which reports that the premium cable network has quietly opted to not pick the series up for a fifth year. During its fall run, Masters of Sex saw its ratings drop to an average of less than 800,000 viewers during live broadcasts on Sunday night, which was considerably less than Ray Donovan and Shameless, which both attracted more than 2 million viewers for each episode’s premiere this season.
Masters of Sex finished its fourth year by welcoming in the 1970s for Bill and Virginia Johnson, the two pioneers of sexual research that the series was based around. Starring Michael Sheen and Lizzy Caplan in those lead roles, the series frequently brought prestige for Showtime, enjoying nominations at both the Golden Globes and Emmys for past seasons, including a Globe nomination for Sheen and an Emmy nomination for Caplan. Guest actress Allison Janney also won an Emmy for the first season.
The fourth season completed its run on Nov. 10.