Mary McCormack detailed the most challenging part of her role on ''In Plain Sight''

Viewers see the final versions of television episodes, and, if we're lucky, some behind-the-scenes moments. What we don't see is how actors prepare themselves to step into the lives of their fictional characters.

It's easy to envision them simply reading their lines in front of a camera, but there's so much more that goes into making a character believable. That process involves a lot of long hours, which is what Mary McCormack found most challenging about playing the main character on In Plain Sight.

"Well, the role is such a nice fit for me. Honestly, I think the most challenging part of this job was just how much I'm in it," McCormack told Fan Bolt in 2008. "I've never really experienced that kind of workload before. You know it's challenging and fulfilling, it's sort of you know, one of those things, be careful what you wish for. It's such a great part, and it's – you know, you see her at work, and you see her at home. The sort of challenge for me was I went to Albuquerque with an eight-week-old and was working sort of 13 to 19-hour days, and for me, that was the most challenging part was just staying afloat."

The actress played U.S. Marshal Mary Shannon, who must hunt down witnesses for federal cases in the witness protection program. She also manages a dysfunctional family and her own personal life. In Plain Sight premiered on June 1, 2008, and produced 61 episodes through five seasons.