Showtime has released the full-length trailer for “Masters of Sex” season two.

The new promo promises more drama surrounding the work of Dr. William Masters (Michael Sheen) and Virginia Johnson (Lizzy Caplan), with their personal affairs inexorably tangling with their professional reputations.  “Keep your heart out of it,” Virginia warns her partner, hinting at what’s to come in the show’s sophomore season.

The series is based on the true events in the lives and careers of Masters and Johnson, pioneers of the science of human sexuality.  “Masters of Sex” received both Golden Globe and WGA Nominations for its first season.

“Masters of Sex” season two premieres Sunday, July 13 at 10 p.m. on Showtime.