After three years and two networks, "Roswell" is coming to an end on Tuesday, May 14 at 9 p.m. on UPN. ET spoke to the show's executive producer/creator JASON KATIMS, who told us that to him the show's hook was its Romeo-and-Juliet-like relationship between Max and Liz.

Based on the Roswell High series of novels by MELINDA METZ, "Roswell" is a combination of sci-fi and teen angst set in a small town in New Mexico. Created for FOX, "Roswell" beamed over to The WB before finishing its third season on UPN.

ET: I thought you had already written an ending when "Roswell" was on The WB, so is this a second ending?

JASON: When it was on The WB, it was a little bit more of a cliffhanger ending where Tess had left the planet with Max's son, and the cliffhanger there was that he vowed to find his son. So, it was definitely left open. This year when we were writing the final episodes, we had the sense that the chances were strong that we were not coming back. So we decided that our goal was to try to bring the series to a satisfying conclusion, especially for the fans who have been with the show all this time.

ET: So are you more interested in wrapping up the story points, or are you going for emotional content?

JASON: Well, certainly in the final episode it is much more about the emotional content and about the relationships. The episode that aired on May 7, tied up a big story point about Max's child, and also resolved the triangle with Tess as Raven returned. So in the final episode, our main concern was to tie up the show emotionally. One of the things that we did was we framed Liz's voice -- which is how we started the show in the pilot. In many ways I think that this final episode has a good feeling for people who have watched the show from the beginning. It feels like the pilot, and it's also a story about Max and Liz moving forward with their relationship in what, I hope, will be a satisfying conclusion to the audience.

ET: I think the fans want them together.

JASON: I hope they do. It's funny because writers normally can't think about what the fans want to see happen, what they are happy about and what they are not happy about, because you have to tell the story and it won't be what the audience wants. Sometimes you have to keep Max and Liz apart for a while in order to keep the story going, but in this final episode -- I wrote it with RON MOORE, who is also an executive producer on the show -- it was the one time that I really had the audience in mind when I was writing it. I really wanted to do my best to have the series come to a conclusion that would be emotionally satisfying. I am very happy with this final episode. I think that it is a return to where the show started and that is what we set out to do.

ET: When you look back, do you have any idea what you could have done in order to get a season four?

JASON: I don't know if there is anything that we could have done. In a sense, we were on borrowed time this year anyways. The show was literally cancelled for several days last year before UPN brought it back, and, honestly, I think that the writing was on the wall when we premiered (on The WB). I don't think that it had anything to do with the stories or anything that we did this year.

I think, unfortunately, we did not do good in the timeslot. I think that we just got creamed. That is the truth. That was one of the biggest disappointments to me because we had an incredible lead-in with "Buffy."

The competition was incredible. Frankly, the success of "Smallville" was really tough for us because that was essentially what we thought would be our audience.

Again, that happened from when we premiered. From the first moment, the audience never came to check us out. So I don't think that there was anything that we could have done to change that. I think that we did some very strong episodes in the third season, and I think that we set out to do what we wanted. So, I don't look at it like, "Oh, if we had just done that then we would have gotten another season."

ET: Well the fans still have not given up. I understand that there is a fundraiser underway on crashdown.com.

JASON: Our fans are an extraordinary group of people. They constantly amaze me. In addition to the fact that I think they literally kept the show on the air, I really think that without the fans' campaigns both the first and the second year, I don't think that the show would have come back

In addition to that, they have raised thousand and thousands of dollars for different causes over the past few years. For me that kind of support and passion is such a powerful thing and that is something that honestly will always stay with me. I don't know if that will ever happen to me again. It's a very special thing.

ET: Were you into sci-fi before Roswell?

JASON: No, I was not really involved in a sci-fi show. Everything that I had done before this was more relationship driven. I was not even a science fiction buff or fan per se. I was given the Roswell High novel in the book series (by MELINDA METZ) that the pilot was based on.

Before I read that there was a particular kind of show that I wanted to develop, and it had nothing to do with science fiction. What I wanted to do was a show that was based around a Romeo and Juliet romance with two young leads. The obvious setting for that might be a high school, but I wanted to find a Romeo-and-Juliet-type situation meaning there was a really compelling reason why these two people couldn't be together or being together would create problems for them.

When I read the book, what really drove me to the story was that. It was a great relationship where the two heroes had a lot to overcome in order to be together. They were different life forms, so it was exactly what I was looking to do in a very unexpected way. So that is how I got involved in it, and by the end I had learned a tremendous amount about doing storylines that were more imaginative than other storylines that I had been dealing with before that.

ET: So what is next for you?

JASON: I have no idea. (laughs)

ET: Movies? TV? I know you are a playwright also.

JASON: Yes, I am definitely interested in continuing to write for theater and I would like to do another feature at some point. My main goal is to continue with television and probably try to do another show over the next year or two.

ET: Any possibility "Roswell" will become a motion picture?

JASON: People have actually proposed that idea to me but I don't think that anything like that is being planned right now. But we will see.

ET: Do you have enough episodes for syndication or cable?

JASON: Yes, the studio has made a deal with the SCI FI channel which I think starts in January.