LOS ANGELES (Variety.com) - The troublemaking Gallagher clan returns to Showtime on January 11, and after a particularly dark fourth season -- which found Fiona in jail and Frank dying of liver failure -- the series' stars say things are looking up this time around.

"Things have to get better for Fiona," says Emmy Rossum, "because they got really rough last year for her with jail and drugs. She's going to be a little more introspective, and a little slower to throw the first punch."

Her ever-dramatic love life, too, is going to get a bit more complicated: She'll experience rejection for the first time.

"She's hot in pursuit of Dermot Mulroney, who's not that into her, so she's kind of a mess," reports Rossum. "He's in NA (Narcotics Anonymous) and trying to keep on the straight and narrow, and with her drug history, she's not good for a recovering junkie like him."

Her performance is winning raves from her co-star, William H. Macy. "They're giving her outrageously funny things to do, along with some real drama," he says. "Emmy is just making hay with this."

One of the issues she confronts this season is "Am I going to turn out to be my father?" he says. "In a very left-handed way, they smack her in the face with it."

Macy, who recently earned both Golden Globe and Screen Actors Guild nominations, admits he has his own work cut out for him this year: "This season is stunning for me: It starts slowly, but it's a big finish."

"I've done four years where Frank was a little bit toasted in every single scene," he notes. "I went all the way from completely sloppily inebriated to just a little buzzed. (Now) it's just fantastic to be clear-eyed, even if it is sometimes through a narcotic haze."

Meanwhile, Lip (Jeremy Allen White) continues with his trials and tribulations at college, struggling with the limitations of his background as he interacts with the blue bloods he meets at school. "While these other kids have the support of their family, he's realizing how on his own he is -- and always has been," says Macy. "Luckily, the ladies seem to find it irresistible."

As for the rest of the brood, "Oh, jeez, wait until you see what happens with Carl and the boys," he teases.

"It's been a remarkable five years," adds Rossum. "I've grown so much. And I couldn't have asked for a better teammate in Macy."