Primary Content Credit: Courtesy of (C) Mainstreet Pictures LTD Next week, we'll welcome the return of two of our favorite Masterpiece detectives, welcome a brand new crime-solver to our Sunday night line-up, learn the stories behind some true American treasures and more. Take a look at what's coming up! Unforgotten on Masterpiece: Season 4 - Sunday, July 11 at 9 PM In the series' most dramatic season, Cassie and Sunny investigate a cold case with alarming links to the police force. Can the force ever really be trusted, and will Cassie and Sunny find themselves on the wrong side of the law? Professor T - Sunday, July 11 at 10 PM