Castle Castle

Most Castle fans already know that when the mystery drama checks in for Season 3, our favorite crime-solving odd couple will still be dancing around their feelings for one another. More surprising is that viewers will also see Castle on the other side of the law after he returns from his romantic Hamptons getaway. "It's one of those things — be careful what you wish for," star Nathan Fillion tells about his character's arrest in Monday's season opener.

And that's just the first episode. The show's cast and crew revealed what other surprises are in store for Season 3, including a cross-country trip and a possible cameo from one of True Blood's main men.

Exclusive: Young and the Restless' Eden Riegel headed to Castle

Guest Star Love: Jennifer Love Hewitt is in talks to appear on the series. "If she joins us for the show, we have a great role for her that would get her very involved in everything," series executive producer Andrew Marlowe says. Jon Huertas also hopes to find a part for real-life pal, True Blood's Alexander Skarsgard. "We were going to offer him a role in this next episode that we're filming, but he's in Hawaii working on Battleship and the role just wasn't the perfect fit," Huertas says. "But he wants to work on the show."

Hello, Hollywood: Stana Katic says the team will head to Los Angeles to solve a crime. But it won't be all work while Castle and Beckett are in the movie capital of the world, as their visit will coincide with developments for the first Nikki Heat movie.

Check out photos from Castle

Fireworks for the Castle Family: Alexis will start her first relationship this year, and actress Molly Quinn says Castle's reaction isn't exactly cool and collected. "There may be some broken dishes ... it's going to be a hurricane reaction," she teases.

Attention to Detail: Marlowe hopes to reward the show's loyal fans by bringing some of the series' supporting players to the forefront. "We're really looking to open these guys up and show some different aspects." A Lanie-centric episode is currently in the works, and fans should keep their eyes peeled for another possible office fling that may take the heat away from Castle and Beckett's romantic tension.

Is Castle — Gasp — the Bad Guy?: Although Castle's decision to run off with ex-wife Gina (Monet Mazur) in the season finale may have left fans scratching their heads, Fillion says viewers will get a better picture of her this year.  "As much as Castle talks a tough game about how mean she was, she's actually a really good person," he says. "So now we get to see a side of Gina that we don't ever hear from Castle ... maybe the fault doesn't always lie with Gina, maybe it lies with Castle."

Castle returns Monday, Sept. 20 at 10/9c on ABC.