Gish plays a woman who loves her husband and loves her kids, yet is desperately unhappy with her life as a dutiful political wife and mother. That leads to big trouble for Eileen, and a juicy part for Gish.

"It was good to go dark. And I go dark," Gish said. "I go really - I mean, I think all of us are morally challenged, and I certainly go down a slippery slope with drugs and sex. And it was a blast."

In a recent phone interview, Gish said her character feels trapped - trapped in a family triangle with her husband, his brother and their domineering mother, trapped by her husband's ambition, and trapped on The Hill, the close-knit Irish neighborhood where everyone lives on top of everyone else.

"For her, The Hill is a prison," Gish said.

Filling out Eileen's bio, Brotherhood writer Blake Masters said she loves her husband, but she got married at 19, too young to know what she was getting into.

But now she knows enough to realize that her gangster brother-in-law Michael Caffee's return to Providence means trouble for her and her family.

Masters said he wanted to avoid the cliches of the philandering politician when writing Brotherhood, so Tommy Caffee never swears and never cheats. Eileen Caffee, though, is another story.

Eileen might feel trapped on The Hill, but Gish, who was born in New Mexico and grew up in Iowa, said she thoroughly enjoyed her stay in Providence while Brotherhood was filming.

She stayed in an apartment on Benefit Street, and would go to the Coffee Exchange on Wickenden Street every morning.

"Providence was full of warm, welcoming people, and there is culture and academia out the wazoo," Gish said.

(Her husband, Wade Allen, worked as a stunt coordinator on the Brotherhood pilot.)

Gish, whose TV credits include The West Wing and The X-Files, said the word was out in Hollywood that the project known as "The Untitled Blake Masters Script" had some great roles for actresses.

"I fought to get that part," Gish said. "I've done a lot of network TV, and it's a real pleasure to do something that's darker and deeper."

Gish said the show takes some chances, and now she's hoping that it will find an audience.

"Being cowardly reaps no rewards," she said. "The Sopranos shows there's an audience that can deal with violence, but woven around that Brotherhood has a whole series of human stories.

"I think the show really found its legs around midseason. It can be complicated and messy, just like people are complicated and messy."

Gish said she's crossing her fingers that Showtime will renew Brotherhood for a second season - and maybe more.