"Masters of Sex," the Showtime drama starring Michael Sheen and Lizzy Caplan as real life sex specialists Dr. William H. Masters and Virginia Johnson, was an overnight hit. Now, the network has released a trailer for the second of season, which looks darker, sexier and a lot more scandalous. 

In the trailer we see the lines blur between Sheen and Caplan's professional and romantic relationship. Season 2 also stars Caitlin Fitzgerald, Teddy Sears and Annaleigh Ashford. Guest stars include Beau Bridges, Allison Janney, Julianne Nicholson and Sarah Silverman.

Season 2 of "Masters of Sex" will premiere on Showtime on July 13th at 10pm. Check out the trailer below.