“Thirtysomething guy with arrested development falls for thirtysomething woman with arrested development, but moving out of his childhood bedroom proves too much. Tragedy ensues.”

That’s the nutshell summary of "Dark Horse," the new film from writer-director Todd Solondz ("Happiness"). A glimpse into a darker side of delayed adulthood, it stars newcomer Jordan Gelber as its leading man-child and Selma Blair as leading woman-child, with a stellar supporting cast that includes Mia Farrow and Christopher Walken.

We discussed the poignant dark comedy with Solondz and learned how the film tempted Mia Farrow out of retirement, what the director's version of a "lighthearted romantic comedy" is, who his influences are and more.

What does the phrase -- and the title of the movie -- "dark horse" mean to you?

Well, I don't want to give anything away about how things end up in the movie, but certainly a dark horse is something of a long shot in life, and one can win -- can bet on a long shot and it can win -- or not win. So it's that understanding of the idiom.

It's a darker side of arrested development than typically portrayed in film and TV. Where did your version of that, and these characters, come from?

I'm sure it's a composite of people I know, have known, as well as the stories I've been told and so forth. I think the movie does function, you’re right, as a kind of alternative to the [Judd] Apatow "40-Year-Old Virgin" movie. It's a different kind of movie. A different kind of direction, but [it] certainly addresses this "man-child" kind of character. I was very moved by the idea of this character who clings so much to his youth.

The film also has a bit of an existential tone to it. For example, Abe (played by Gelber) hopelessly remarking that "we're all horrible people." Was there any philosophical idea behind the story?

Well, Abe says that, but I think the movie serves to undermine that statement because one sees at the end of the film the secretary who cares for him that worked closely with him, but he was blind to her affections. There's a kind of poignancy to that. That we are in fact not what Abe thinks we are.

What also makes it seem so surreal is the breakdown of reality when Abe starts imagining he’s talking to the secretary and other characters who aren't really there.

I wanted to access, through his fantasy life, the internal drama of his life -- his internal struggles, struggling really to grow up. You can be 35 years old, but that doesn't make you quite a grown-up. This is someone who is struggling to find in himself the courage to accept and embrace Miranda. So it's just another technique, the breakdown, a way of finding what dynamic within him makes him able to survive and grow up.

What do you hope audiences will take away from the film?

I approach things always on an emotional level. If I didn’t care about my characters, I couldn’t make a movie about them. I suppose I challenge the audience to embrace those characters who on the surface are not very likable. He's [Abe] very much that kind of pampered, spoiled child, and it’s what makes him tick that makes me feel for him. It's not so much his change as it is the audience's change of understanding what this person is about and why he is the way he is. That is what I hope the audience is going to be moved by in the end.

Like "Dark Horse," your past films filter reality through a darker lens. Are you attracted to darker stories? Do you have a master plan for your film legacy?

I don't have any master plan. I never had any plan except to make each movie one at a time. There's no cunning or calculation to this so-called career. I write a script and then I make the movie and see what comes of it. This movie, I wanted to not have any of the so-called controversial subject matter that I had become somewhat known for. I wanted to get away from that. It just felt it would be less pressure for me to explore this character study without being distracted by the burden of those taboos and so forth … Am I attracted to darker themes? I don't think if it's dark or it's light. I just think about what I find funny and what excites me and if people call it dark, so be it.

Do you ever see yourself making a lighthearted romantic comedy?

Well, I thought that's what this was, but I've learned that I was wrong. [laughs] You know, you make a movie and you never know how anyone's going to take it. I thought this was my lighthearted romantic comedy.

You're just missing Katherine Heigl or J.Lo. Speaking of female leads, how did Selma Blair become involved in the film?

It's kind of a continuation of the character she played in “Storytelling,” and I love working with her. I think she's just so gifted and beautiful. I felt so lucky she was available to do the movie. We both were so excited and happy that we could work together again.

She was very subtle yet affecting.

Yes, she doesn’t make it obvious. You know it's hard to articulate these things when you start talking about actors because almost anything you say sounds so generic, but really I can just say that through her, I can speak a common language. I'm very fortunate I've been able to find such an actress.

You had quite a high-caliber cast overall: Mia Farrow, Christopher Walken … Had you worked with all of them before?

No, the only one I'd worked with before was Selma; but Mia, I really thought she'd be super as Abe's mom, but I didn't know that she'd be available or interested. When we met she told me she was retired from acting and that she hadn't even read the script, but that her son Ronan was a big admirer of my films, and he implored her, "Please, you gotta do this," and so she did it. And she was such a total joy, a delight -- really fun, funny, smart. I loved working with her.

Was Jordan Gelber an unknown that you discovered?

He auditioned for me on another movie, and then we saw him in a play a couple of years ago and [I] was really impressed with his work and thought he'd be very suitable for this script. I just didn't know if I could get the movie financed with an unknown. But I was able to supply a greater wattage in the supporting cast, and not have to cast a star, and there weren’t any stars there were quite so appropriate or suitable as Jordan Gelber.

You have such a unique perspective as a director. What writers or directors do you think most influenced your style?

Sure, there's tons. I'm just thinking recently about how I loved Lynda Barry a few years ago, her comic strip ["Ernie Pook's Comeek"]. When I was much younger I loved Paul Bartel and George Kuchar, who just died. He had a big impact on me. Today, I find myself more influenced by people that are a little older than me, but I'll steal from whoever comes up with stuff that excites me.

Do you have any other projects in the works?

I'm looking for money. My job is primarily looking for money all the time, so that's what I'm up to right now.

Would you ever consider aiming for a popcorn-movie blockbuster to make things easier?

I think every script's a blockbuster, but that just shows you how weak my judgment is.

Can you give us a sneak preview of the plot of your next film?

I never like to jinx myself. I can just say that my next movie will be in Texas. Not sure how intriguing that will be for readers, though ... [laughs]