Katherine Heigl knew Roswell was a hit when -- well, when her sister called. "She said, ‘The show was great this week!’ " Heigl recalls. "She would get into it and discuss things about the show and ask me questions. It was really weird that my sister, who lives across the country, was watching me on Roswell. It was strange to realize that I was on TV every week. I had always done film. And, going into the show, I didn’t think it would feel that different from doing film. But it is. I’m getting calls from my sister, my friends. I go out and I’m recognized so much more, and that’s because Roswell is on every week. Before that, I would be recognized occasionally by someone who knew me from My Father the Hero or Under Siege 2 or maybe Bride of Chucky. Now, when I go out to the mall, people will say, ‘Hey, aren’t you on that show Roswell?’ The whole thing is weird. Because I’m in their living room every week, people feel like they know me. I love it. It’s so nice to know people like the show and that I have a job for at least the next nine months."

Roswell, for those few who don’t know by now, centers on Isabel Evans (Heigl), her brother Max (Jason Behr) and their friend Michael (Brendan Fehr), three aliens growing up in Roswell, New Mexico, as average human teens. The three live in constant fear of being found out, something that could easily happen at any moment, particularly given that Max has revealed both his powers and the truth about himself to Liz (Shiri Appleby), the high school girl he adores, and that Liz’s pals, Maria (Majandra Delfino) and Alex (Colin Hanks), know the trio’s secret and tend to open their mouths at inopportune moments.

In a season that saw so anticipated a genre show as Harsh Realm flame out after three episodes, what is it about Roswell that appeals to audiences? Heigl thinks she knows. "It’s a little bit more mature and sophisticated than just any regular teenage show," she reasons. "We’re dealing with the fugitive aspect, the alien aspect. Our lives are in danger. Because our situation is so delicate, anybody involved with us or around us is suddenly in a dangerous situation, too. There’s that element to it, that suspense, and there’s also the chase and the constant search for some sort of knowledge or information, so that we can figure out what the heck we’re doing here on Earth. That makes it a little more interesting than just dealing with the day-to-day high school stuff."

Though many Roswell fans revel in the often heart-wrenching Max-Liz relationship, there’s something to be said for the edge that Isabel lends to the proceedings. She speaks her mind and displays what can perhaps best be described as a smug superiority complex. And, taking into account the fact that Isabel does indeed possess superior otherworldly powers, it’s hard to begrudge Isabel her imperiousness. "Initially, I thought, ‘Is this just an insecurity of hers? Maybe that’s why she behaves this way.’ And then," Heigl notes. "I thought, ‘No, it’s really not.’ Isabel knows that she’s unique. She knows that she has something over everybody else, and she’s confident in that and confident in herself and who she is. This secret--even though it’s dangerous, even though she’s afraid of it-makes her aware of just how unique she is. She’s so above it all. It’s great, but in future episodes, you’ll see that toned down just a bit. It’s also a defense mechanism in some respects, and they don’t want to overdo it.

"Isabel is one of those great characters that I’ve always wanted to play. She has such complexity. She’s the girl who wants to be like everyone else. She wants to fit into the normal high school scene and be popular, have boyfriends and wear cool clothes. At the same time, she has these extraordinary powers, this big secret. She is special. So, she wants to fit in, but she’s really different, and she’s fighting between these two sides of herself. Obviously, the stakes are a little higher, because she could get killed if her secret gets out."